adding graphs, beginning writing, added concentration/fermi level

This commit is contained in:
andy 2021-04-20 21:19:15 +01:00
parent 80a04c4b21
commit 4ce1569a86
36 changed files with 1057 additions and 72 deletions

View File

@ -8,20 +8,20 @@ close all; clear all; clc;
%% FLAGS & OPTIONS %% FLAGS & OPTIONS
%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%
DISPLAY_HZ = true; DISPLAY_HZ = true; % convert rads back to Hz for presenting
MIN_F = 0; MIN_F = 9;
MAX_F = 15; % Hz MAX_F = 15; % Hz
F_TOTAL = 50; F_TOTAL = 50; % number of points to generate
MAX_Y = 17; % carriers (m-2) MAX_Y = 18; % carriers (m-2)
Y_TOTAL = 50; Y_TOTAL = 50; % number of points to generate
% EXCITATION_TYPE = 'intra'; % EXCITATION_TYPE = 'intra';
EXCITATION_TYPE = 'inter'; % EXCITATION_TYPE = 'inter';
%EXCITATION_TYPE = 'all'; EXCITATION_TYPE = 'all';
t = 2.8; % eV t = 2.8; % eV, energy scale for Fermi velocity
%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%
%% CALCULATE %% CALCULATE
@ -30,30 +30,66 @@ t = 2.8; % eV
f_vals = logspace(MIN_F, MAX_F, F_TOTAL); % hz f_vals = logspace(MIN_F, MAX_F, F_TOTAL); % hz
f_vals = f_vals .* (2*pi); % rads-1 f_vals = f_vals .* (2*pi); % rads-1
carrier_vals = logspace(0, MAX_Y, Y_TOTAL); % m-2 % Carrier Density
%carrier_vals = carrier_vals + 273.15; %%%%%%%
% carrier_vals = logspace(0, MAX_Y, Y_TOTAL); % m-2
% below turns turns carrier densities into Fermi energies %
fermi_vals = zeros(1, length(carrier_vals)); % % below turns turns carrier densities into Fermi energies
for carr=1:length(carrier_vals) % fermi_vals = zeros(1, length(carrier_vals));
fermi_vals(carr) = fermi_from_carrier_density(carrier_vals(carr), ev_to_j(t)); % for carr=1:length(carrier_vals)
end % fermi_vals(carr) = fermi_from_carrier_density(carrier_vals(carr), ev_to_j(t));
% end
%
% % CALCULATE SHEET CONDUCTIVITY
% cond = zeros(length(f_vals),... % frequency
% length(fermi_vals),... % fermi
% 2); % intra/inter
% for freq=1:length(f_vals)
% for y=1:length(fermi_vals)
%
% cond(freq, y, :) = sheet_conductivity(f_vals(freq),... % omega (rads-1)
% fermi_vals(y),... % fermi_level (J)
% 300,... % temp (K)
% 5e-12); % scatter_lifetime (s)
% end
% end
% Temperature
%%%%%%%
temp_vals = linspace(0, 2230, Y_TOTAL); % K
% CALCULATE SHEET CONDUCTIVITY % CALCULATE SHEET CONDUCTIVITY
cond = zeros(length(f_vals), % frequency cond = zeros(length(f_vals),... % frequency
length(fermi_vals), % fermi length(temp_vals),... % fermi
2); % intra/inter 2); % intra/inter
for freq=1:length(f_vals) for freq=1:length(f_vals)
for y=1:length(fermi_vals) for y=1:length(temp_vals)
cond(freq, y, :) = sheet_conductivity(f_vals(freq), % omega (rads-1) cond(freq, y, :) = sheet_conductivity(f_vals(freq),... % omega (rads-1)
fermi_vals(y), % fermi_level (J) fermi_from_carrier_density(1.3e13*10000, ev_to_j(t)),... % fermi_level (J)
300, % temp (K) temp_vals(y),... % temp (K)
5e-12); % scatter_lifetime (s-1) 5e-12); % scatter_lifetime (s)
end end
end end
% Scatter Lifetime
%%%%%%%
% scatt_vals = logspace(-11, -14, Y_TOTAL); % s-1
%
% % CALCULATE SHEET CONDUCTIVITY
% cond = zeros(length(f_vals),... % frequency
% length(scatt_vals),... % fermi
% 2); % intra/inter
% for freq=1:length(f_vals)
% for y=1:length(scatt_vals)
%
% cond(freq, y, :) = sheet_conductivity(f_vals(freq),... % omega (rads-1)
% fermi_from_carrier_density(1.3e13*10000, ev_to_j(t)),... % fermi_level (J), ttf = 1.3e13*10000, cocp2 = 2.2e13*10000
% 300,... % temp (K)
% scatt_vals(y)); % scatter_lifetime (s)
% end
% end
%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%
%% RENDER %% RENDER
%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%
@ -62,23 +98,37 @@ if DISPLAY_HZ % divide radians back to hertz
f_vals = f_vals ./ (2*pi); f_vals = f_vals ./ (2*pi);
end end
y_vals = temp_vals;
% cond = sign(cond).*log10(abs(cond));
figure(1) figure(1)
if EXCITATION_TYPE == 'intra' if strcmp(EXCITATION_TYPE, 'intra')
surf(f_vals, carrier_vals, transpose(real(cond(:, :, 1)))); surf(f_vals, y_vals, transpose(real(cond(:, :, 1))));
elseif EXCITATION_TYPE == 'inter' title('2D Real Intraband Sheet Conductivity');
surf(f_vals, carrier_vals, transpose(real(cond(:, :, 2)))); elseif strcmp(EXCITATION_TYPE, 'inter')
surf(f_vals, y_vals, transpose(real(cond(:, :, 2))));
title('2D Real Interband Sheet Conductivity');
else else
surf(f_vals, carrier_vals, transpose(real(sum(cond, 3)))); surf(f_vals, y_vals, transpose(real(sum(cond, 3))));
title('2D Real Sheet Conductivity');
end end
h = gca;
rotate3d on rotate3d on
grid; grid;
colorbar; colorbar;
set(h, 'xscale', 'log') axis tight;
set(h, 'yscale', 'log') set(gca, 'xscale', 'log')
title('2D Sheet Real Conductivity'); % set(gca, 'yscale', 'log')
ylabel('Net Carrier Density (m-2)'); % set(gca, 'zscale', 'log')
zlabel('Conductivity (S/m)');
set(gca, 'ColorScale', 'log')
% ylabel('Net Carrier Density (m^{-2})');
ylabel('Temperature (K)');
% ylabel('Scatter Lifetime (s)');
zlabel('Conductivity (S)');
if DISPLAY_HZ if DISPLAY_HZ
xlabel('Frequency (Hz)'); xlabel('Frequency (Hz)');
else else
@ -86,23 +136,32 @@ else
end end
figure(2) figure(2)
if EXCITATION_TYPE == 'intra' if strcmp(EXCITATION_TYPE, 'intra')
surf(f_vals, carrier_vals, transpose(imag(cond(:, :, 1)))); surf(f_vals, y_vals, transpose(imag(cond(:, :, 1))));
elseif EXCITATION_TYPE == 'inter' title('2D Imaginary Intraband Sheet Conductivity');
surf(f_vals, carrier_vals, transpose(imag(cond(:, :, 2)))); elseif strcmp(EXCITATION_TYPE, 'inter')
surf(f_vals, y_vals, transpose(imag(cond(:, :, 2))));
title('2D Imaginary Interband Sheet Conductivity');
else else
surf(f_vals, carrier_vals, transpose(imag(sum(cond, 3)))); surf(f_vals, y_vals, transpose(imag(sum(cond, 3))));
title('2D Imaginary Sheet Conductivity');
end end
surf(f_vals, carrier_vals, transpose(imag(sum(cond, 3))));
h = gca;
rotate3d on rotate3d on
grid; grid;
colorbar; colorbar;
set(h, 'xscale', 'log') axis tight;
set(h, 'yscale', 'log') set(gca, 'xscale', 'log')
title('2D Sheet Imaginary Conductivity'); % set(gca, 'yscale', 'log')
ylabel('Net Carrier Density (m-2)'); % set(gca, 'zscale', 'log')
zlabel('Conductivity (S/m)');
% set(gca, 'ColorScale', 'log')
% ylabel('Net Carrier Density (m^{-2})');
ylabel('Temperature (K)');
% ylabel('Scatter Lifetime (s)');
zlabel('Conductivity (S)');
if DISPLAY_HZ if DISPLAY_HZ
xlabel('Frequency (Hz)'); xlabel('Frequency (Hz)');
else else

View File

@ -8,14 +8,17 @@ close all; clear all; clc;
%% FLAGS & OPTIONS %% FLAGS & OPTIONS
%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%
DISPLAY_HZ = true; DISPLAY_HZ = true; % convert rads back to Hz for presenting
MIN_F = 9; MIN_F = 9;
MAX_F = 15; MAX_F = 15;
F_TOTAL = 1e2; F_TOTAL = 1e2; % number of points to generate
% EXCITATION_TYPE = 'intra'; % EXCITATION_TYPE = 'intra';
EXCITATION_TYPE = 'inter'; % EXCITATION_TYPE = 'inter';
%EXCITATION_TYPE = 'all'; EXCITATION_TYPE = 'all';
TWO_SERIES = true; % for comparing two dopants
%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%
%% CALCULATE %% CALCULATE
@ -27,10 +30,20 @@ x_vals = x_vals .* (2*pi); % rads-1
% CALCULATE SHEET CONDUCTIVITY % CALCULATE SHEET CONDUCTIVITY
cond = zeros(length(x_vals), 2); cond = zeros(length(x_vals), 2);
for x=1:length(x_vals) for x=1:length(x_vals)
cond(x, :) = sheet_conductivity(x_vals(x), % omega (rads-1) cond(x, :) = sheet_conductivity(x_vals(x),... % omega (rads-1)
fermi_from_carrier_density(2.2e17, ev_to_j(2.8)), % fermi_level (J) fermi_from_carrier_density(1.3e13*10000, ev_to_j(3)),... % fermi_level (J)
300, % temp (K) 300,... % temp (K)
0.135e-12); % scatter_lifetime (s-1) 1e-12); % scatter_lifetime (s)
end
if TWO_SERIES
cond2 = zeros(length(x_vals), 2);
for x=1:length(x_vals)
cond2(x, :) = sheet_conductivity(x_vals(x),... % omega (rads-1)
fermi_from_carrier_density(2.2e13*10000, ev_to_j(3)),... % fermi_level (J)
300,... % temp (K)
1e-12); % scatter_lifetime (s)
end
end end
if DISPLAY_HZ % divide radians back to hertz if DISPLAY_HZ % divide radians back to hertz
@ -41,24 +54,59 @@ end
%% RENDER %% RENDER
%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%
RE_COLOUR = 'r';
IM_COLOUR = 'r--';
RE_COLOUR2 = 'b';
IM_COLOUR2 = 'b--';
LW = 1.5;
figure(1); figure(1);
hold on; hold on;
%plot(x_vals, real(cond)); % INTRA
if EXCITATION_TYPE == 'intra' if strcmp(EXCITATION_TYPE, 'intra')
semilogx(x_vals, real(cond(:, 1))); plot(x_vals, real(cond(:, 1)), RE_COLOUR, 'LineWidth', LW);
semilogx(x_vals, imag(cond(:, 1))); plot(x_vals, imag(cond(:, 1)), IM_COLOUR, 'LineWidth', LW);
elseif EXCITATION_TYPE == 'inter'
semilogx(x_vals, real(cond(:, 2))); if TWO_SERIES
semilogx(x_vals, imag(cond(:, 2))); plot(x_vals, real(cond2(:, 1)), RE_COLOUR2, 'LineWidth', LW);
plot(x_vals, imag(cond2(:, 1)), IM_COLOUR2, 'LineWidth', LW);
end
title('2D Intraband Sheet Conductivity');
% INTER
elseif strcmp(EXCITATION_TYPE, 'inter')
plot(x_vals, real(cond(:, 2)), RE_COLOUR, 'LineWidth', LW);
plot(x_vals, imag(cond(:, 2)), IM_COLOUR, 'LineWidth', LW);
if TWO_SERIES
plot(x_vals, real(cond2(:, 2)), RE_COLOUR2, 'LineWidth', LW);
plot(x_vals, imag(cond2(:, 2)), IM_COLOUR2, 'LineWidth', LW);
end
title('2D Interband Sheet Conductivity');
% COMPLEX
else else
semilogx(x_vals, real(sum(cond, 2))); plot(x_vals, real(sum(cond, 2)), RE_COLOUR, 'LineWidth', LW);
semilogx(x_vals, imag(sum(cond, 2))); plot(x_vals, imag(sum(cond, 2)), IM_COLOUR, 'LineWidth', LW);
if TWO_SERIES
plot(x_vals, real(sum(cond2, 2)), RE_COLOUR2, 'LineWidth', LW);
plot(x_vals, imag(sum(cond2, 2)), IM_COLOUR2, 'LineWidth', LW);
end
title('2D Sheet Conductivity');
end end
set(gca,'Xscale','log')
% set(gca,'Yscale','log')
axis tight
if TWO_SERIES
legend('Real TTF', 'Imaginary TTF', 'Real CoCp2', 'Imaginary CoCp2');
else
legend('Real', 'Imaginary'); legend('Real', 'Imaginary');
end
grid; grid;
title('2D Sheet Conductivity'); ylabel('Conductivity (S)');
ylabel('Conductivity (S/m)');
if DISPLAY_HZ if DISPLAY_HZ
xlabel('Frequency (Hz)'); xlabel('Frequency (Hz)');
else else

View File

@ -0,0 +1,52 @@
%% fermi_conc.m
%%
%% present fermi levels for different carrier concentrations
close all; clear all; clc;
%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% FLAGS & OPTIONS
%%%%%%%%%%%%%%%%%%%%%%%%%%%
MIN_CONC = 0;
MAX_CONC = 20;
X_TOTAL = 1e2; % number of points to generate
DISP_EV = true;
%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% CALCULATE
%%%%%%%%%%%%%%%%%%%%%%%%%%%
x_vals = logspace(MIN_CONC, MAX_CONC, X_TOTAL); % hz
% CALCULATE SHEET CONDUCTIVITY
energy = zeros(1, length(x_vals));
for x=1:length(x_vals)
temp = fermi_from_carrier_density(x_vals(x), ev_to_j(2.8)); % scatter_lifetime (s)
if DISP_EV
temp = j_to_ev(temp);
end
energy(1, x) = temp;
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% RENDER
%%%%%%%%%%%%%%%%%%%%%%%%%%%
% INTRA
plot(x_vals, energy, 'LineWidth', 1.5);
title('Fermi level for differing carrier concentrations');
set(gca,'Xscale','log')
set(gca,'Yscale','log')
% axis tight
grid;
xlabel('Carrier Concentration (m^{-2})');
if DISP_EV
ylabel('Fermi Energy (eV)');
else
ylabel('Fermi Energy (J)');
end

View File

@ -1,4 +1,5 @@
function eV = j_to_ev(j) function eV = j_to_ev(j)
%J_TO_EV Transform Joules into electron-volts
eV = j / 1.602e-19; eV = j / 1.602e-19;
end end

View File

@ -0,0 +1,58 @@
@article{yao,
author = {Yao, Yu and Kats, Mikhail A. and Genevet, Patrice and Yu, Nanfang and Song, Yi and Kong, Jing and Capasso, Federico},
doi = {10.1021/nl3047943},
issn = {1530-6984},
journal = {Nano Letters},
note = {doi: 10.1021/nl3047943},
number = {3},
pages = {1257--1264},
publisher = {American Chemical Society},
risfield_0_da = {2013/03/13},
risfield_1_t2 = {Nano Letters},
title = {Broad Electrical Tuning of Graphene-Loaded Plasmonic Antennas},
url = {https://pubs.acs.org/doi/10.1021/nl3047943},
urldate = {2021-04-19},
volume = {13},
year = {2013}
}
@article{david-paper,
author = {Samuels, Alexander J. and Carey, J. David},
doi = {10.1021/acsami.5b05140},
issn = {1944-8244},
journal = {ACS Applied Materials \& Interfaces},
note = {doi: 10.1021/acsami.5b05140},
number = {40},
pages = {22246--22255},
publisher = {American Chemical Society},
risfield_0_da = {2015/10/14},
risfield_1_t2 = {ACS Applied Materials \& Interfaces},
title = {Engineering Graphene Conductivity for Flexible and High-Frequency Applications},
url = {https://pubs.acs.org/doi/pdf/10.1021/acsami.5b05140},
urldate = {2021-04-20},
volume = {7},
year = {2015}
}
@article{graphene-high-temp,
abstract = {Heat has always been a killing matter for traditional semiconductor machines. The underlining physical reason is that the intrinsic carrier density of a device made from a traditional semiconductor material increases very fast with a rising temperature. Once reaching a temperature, the density surpasses the chemical doping or gating effect, any p-n junction or transistor made from the semiconductor will fail to function. Here, we measure the intrinsic Fermi level (|EF| = 2.93 kBT) or intrinsic carrier density (nin = 3.87 {\texttimes} 10(6) cm(-2)K(-2){\textcdot} T(2)), carrier drift velocity, and G mode phonon energy of graphene devices and their temperature dependencies up to 2400 K. Our results show intrinsic carrier density of graphene is an order of magnitude less sensitive to temperature than those of Si or Ge, and reveal the great potentials of graphene as a material for high temperature devices. We also observe a linear decline of saturation drift velocity with increasing temperature, and identify the temperature coefficients of the intrinsic G mode phonon energy. Above knowledge is vital in understanding the physical phenomena of graphene under high power or high temperature.},
author = {Yin, Yan and Cheng, Zengguang and Wang, Li and Jin, Kuijuan and Wang, Wenzhong},
doi = {10.1038/srep05758},
issn = {2045-2322},
journal = {Scientific reports},
month = jul,
pages = {5758--5758},
publisher = {Nature Publishing Group},
risfield_0_db = {PubMed},
risfield_1_la = {eng},
risfield_2_an = {25044003},
risfield_3_u1 = {25044003[pmid]},
risfield_4_u2 = {PMC4104577[pmcid]},
risfield_5_u4 = {srep05758[PII]},
title = {Graphene, a material for high temperature devices--intrinsic carrier density, carrier drift velocity, and lattice energy},
url = {https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4104577},
urldate = {2021-04-20},
volume = {4},
year = {2014}
}

View File

@ -21,7 +21,7 @@ minimalistic
todonotes todonotes
\end_modules \end_modules
\maintain_unincluded_children false \maintain_unincluded_children false
\language english \language british
\language_package default \language_package default
\inputencoding auto \inputencoding auto
\fontencoding global \fontencoding global
@ -97,7 +97,7 @@ todonotes
\defskip medskip \defskip medskip
\is_math_indent 0 \is_math_indent 0
\math_numbering_side default \math_numbering_side default
\quotes_style english \quotes_style british
\dynamic_quotes 0 \dynamic_quotes 0
\papercolumns 1 \papercolumns 1
\papersides 1 \papersides 1
@ -117,7 +117,7 @@ todonotes
\begin_layout Title \begin_layout Title
\size giant \size giant
Graphene Investigations & Conductivity Modelling Graphene Applications & Conductivity Modelling At High Frequencies
\end_layout \end_layout
\begin_layout Author \begin_layout Author
@ -272,18 +272,778 @@ setcounter{page}{1}
Introduction Introduction
\end_layout \end_layout
\begin_layout Standard
Graphene is a 2D allotrope of carbon with
\end_layout
\begin_layout Standard
This work explores the suitability of graphene for high frequency applications.
Section
\begin_inset CommandInset ref
LatexCommand ref
reference "sec:Applications"
plural "false"
caps "false"
noprefix "false"
\end_inset
presents two applications of graphene that take advantage of it's behaviour
at high frequencies.
Section
\begin_inset CommandInset ref
LatexCommand ref
reference "sec:Sheet-Conductivity-Modelling"
plural "false"
caps "false"
noprefix "false"
\end_inset
presents an investigation into the 2D sheet conductivity of the material.
\end_layout
\begin_layout Section \begin_layout Section
Graphene Applications Applications
\begin_inset CommandInset label
LatexCommand label
name "sec:Applications"
\end_inset
\end_layout \end_layout
\begin_layout Section \begin_layout Section
Sheet Conductivity Modelling Sheet Conductivity Modelling
\begin_inset CommandInset label
LatexCommand label
name "sec:Sheet-Conductivity-Modelling"
\end_inset
\end_layout
\begin_layout Standard
This section presents a model for graphene's high frequency conductivity
using the equation below below
\begin_inset CommandInset citation
LatexCommand cite
key "yao"
literal "false"
\end_inset
.
\end_layout
\begin_layout Standard
\begin_inset Formula
\begin{multline}
\sigma_{s}\left(\omega\right)=\frac{2ie^{2}k_{B}T}{\pi\hbar^{2}\left(\omega+\nicefrac{i}{\tau}\right)}\ln\left(2\cosh\left(\frac{E_{F}}{2k_{B}T}\right)\right)\\
+\frac{e^{2}}{4\hbar}\left(\frac{1}{2}+\frac{1}{\pi}\tan^{-1}\left(\frac{\hbar\omega-2E_{F}}{2k_{B}T}\right)-\frac{i}{2\pi}\ln\left(\frac{\left(\hbar\omega+2E_{F}\right)^{2}}{\left(\hbar\omega-2E_{F}\right)^{2}+4\left(k_{B}T\right)^{2}}\right)\right)\label{eq:2d-conductivity}
\end{multline}
\end_inset
\end_layout
\begin_layout Standard
Taking this equation, the first term accounts for the intraband transitions
while the latter term refers to the interband transitions
\begin_inset CommandInset citation
LatexCommand cite
key "david-paper"
literal "false"
\end_inset
\begin_inset Flex TODO Note (Margin)
status open
\begin_layout Plain Layout
cite
\end_layout
\end_inset
.
These two contributions are separated for reference below,
\end_layout
\begin_layout Standard
\begin_inset Formula
\begin{equation}
\sigma_{s}^{intra}\left(\omega\right)=\frac{2ie^{2}k_{B}T}{\pi\hbar^{2}\left(\omega+\nicefrac{i}{\tau}\right)}\ln\left(2\cosh\left(\frac{E_{F}}{2k_{B}T}\right)\right)\label{eq:intra-conductivity}
\end{equation}
\end_inset
\end_layout
\begin_layout Standard
\begin_inset Formula
\begin{equation}
\sigma_{s}^{inter}\left(\omega\right)=\frac{e^{2}}{4\hbar}\left(\frac{1}{2}+\frac{1}{\pi}\tan^{-1}\left(\frac{\hbar\omega-2E_{F}}{2k_{B}T}\right)-\frac{i}{2\pi}\ln\left(\frac{\left(\hbar\omega+2E_{F}\right)^{2}}{\left(\hbar\omega-2E_{F}\right)^{2}+4\left(k_{B}T\right)^{2}}\right)\right)\label{eq:inter-conductivity}
\end{equation}
\end_inset
\end_layout
\begin_layout Standard
Equation
\begin_inset CommandInset ref
LatexCommand ref
reference "eq:2d-conductivity"
plural "false"
caps "false"
noprefix "false"
\end_inset
was implemented in MatLab, see listing
\begin_inset CommandInset ref
LatexCommand ref
reference "calculation_function"
plural "false"
caps "false"
noprefix "false"
\end_inset
, such that the inter and intraband contributions were returned separately.
This allowed for displaying both aspects independently or together by summing.
From the function it can be seen that the variables are AC frequency,
\begin_inset Formula $\omega$
\end_inset
, the Fermi energy level,
\begin_inset Formula $E_{F}$
\end_inset
, the temperature,
\begin_inset Formula $T$
\end_inset
, and the scatter lifetime,
\begin_inset Formula $\tau$
\end_inset
.
These were varied within reasonable ranges in order to investigate how
such variations affect the conductivity, both as a whole and individually.
\end_layout \end_layout
\begin_layout Subsection \begin_layout Subsection
Results Results
\end_layout \end_layout
\begin_layout Standard
To validate the model, values for TTF and CoCp
\begin_inset script subscript
\begin_layout Plain Layout
2
\end_layout
\end_inset
doping taken from
\begin_inset CommandInset citation
LatexCommand citet
key "david-paper"
literal "false"
\end_inset
(see table
\begin_inset CommandInset ref
LatexCommand ref
reference "tab:david-values"
plural "false"
caps "false"
noprefix "false"
\end_inset
) were simulated and can be seen presented in figure
\begin_inset CommandInset ref
LatexCommand ref
reference "fig:david-simulation-conductivity"
plural "false"
caps "false"
noprefix "false"
\end_inset
.
Similarly to the original, the real component can be seen to begin between
40 and 70 mS before declining to around 0.5
\begin_inset Formula $\mu S$
\end_inset
.
This decline occurs between 20 GHz and 2 THz.
The imaginary component peaks over the same frequency band that the real
component declines and the two intersect at around 150 GHz with a conductance
of 31 mS with CoCp
\begin_inset script subscript
\begin_layout Plain Layout
2
\end_layout
\end_inset
and 24 mS for TTF.
\end_layout
\begin_layout Standard
\begin_inset Float table
wide false
sideways false
status open
\begin_layout Plain Layout
\noindent
\align center
\begin_inset Tabular
<lyxtabular version="3" rows="3" columns="3">
<features tabularvalignment="middle">
<column alignment="center" valignment="top">
<column alignment="center" valignment="top">
<column alignment="center" valignment="top">
<row>
<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
Dopant
\end_layout
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
Carrier Concentration (cm
\begin_inset script superscript
\begin_layout Plain Layout
-2
\end_layout
\end_inset
)
\end_layout
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
Fermi Level (eV)
\end_layout
\end_inset
</cell>
</row>
<row>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
TTF
\end_layout
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
1.3 x 10
\begin_inset script superscript
\begin_layout Plain Layout
13
\end_layout
\end_inset
\end_layout
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
0.41
\end_layout
\end_inset
</cell>
</row>
<row>
<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
CoCp
\begin_inset script subscript
\begin_layout Plain Layout
2
\end_layout
\end_inset
\end_layout
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
2.2 x 10
\begin_inset script superscript
\begin_layout Plain Layout
13
\end_layout
\end_inset
\end_layout
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
0.53
\end_layout
\end_inset
</cell>
</row>
</lyxtabular>
\end_inset
\end_layout
\begin_layout Plain Layout
\begin_inset VSpace defskip
\end_inset
With Fermi velocity energy scale,
\begin_inset Formula $t$
\end_inset
= 3 eV
\end_layout
\begin_layout Plain Layout
\begin_inset Caption Standard
\begin_layout Plain Layout
Carrier concentration values for dopants from
\begin_inset CommandInset citation
LatexCommand citet
key "david-paper"
literal "false"
\end_inset
and the Fermi levels derived from the model, see figure
\begin_inset CommandInset ref
LatexCommand ref
reference "fig:fermi-concentration-func"
plural "false"
caps "false"
noprefix "false"
\end_inset
\begin_inset CommandInset label
LatexCommand label
name "tab:david-values"
\end_inset
\end_layout
\end_inset
\end_layout
\begin_layout Plain Layout
\end_layout
\end_inset
\end_layout
\begin_layout Standard
\begin_inset Float figure
wide false
sideways false
status open
\begin_layout Plain Layout
\noindent
\align center
\begin_inset Graphics
filename ../Resources/david-recreation.png
lyxscale 20
width 60col%
\end_inset
\end_layout
\begin_layout Plain Layout
\begin_inset Caption Standard
\begin_layout Plain Layout
Complex conductivity for TTF and CoCp
\begin_inset script subscript
\begin_layout Plain Layout
2
\end_layout
\end_inset
doping at 300 K with a scatter lifetime of 1 ps
\begin_inset CommandInset citation
LatexCommand cite
key "david-paper"
literal "false"
\end_inset
\begin_inset CommandInset label
LatexCommand label
name "fig:david-simulation-conductivity"
\end_inset
\end_layout
\end_inset
\end_layout
\end_inset
\end_layout
\begin_layout Standard
The Fermi level used to calculate conductance (listing
\begin_inset CommandInset ref
LatexCommand ref
reference "calculation_function"
plural "false"
caps "false"
noprefix "false"
\end_inset
) was derived from the net carrier concentration as a result of doping,
see listing
\begin_inset CommandInset ref
LatexCommand ref
reference "fermi_from_carrier_density"
plural "false"
caps "false"
noprefix "false"
\end_inset
.
The non-linear function can be seen modelled in figure
\begin_inset CommandInset ref
LatexCommand ref
reference "fig:fermi-concentration-func"
plural "false"
caps "false"
noprefix "false"
\end_inset
.
\end_layout
\begin_layout Standard
\begin_inset Float figure
wide false
sideways false
status open
\begin_layout Plain Layout
\noindent
\align center
\begin_inset Graphics
filename ../Resources/fermi-conc.png
lyxscale 20
width 60col%
\end_inset
\end_layout
\begin_layout Plain Layout
\begin_inset Caption Standard
\begin_layout Plain Layout
Fermi level associated with different carrier concentrations
\begin_inset CommandInset label
LatexCommand label
name "fig:fermi-concentration-func"
\end_inset
\end_layout
\end_inset
\end_layout
\end_inset
\end_layout
\begin_layout Subsubsection
Carrier Density
\end_layout
\begin_layout Standard
The general trends for how the dopant-influenced net carrier concentration
influences conductivity can be seen in the surfaces of figure
\begin_inset CommandInset ref
LatexCommand ref
reference "fig:surf-carrier-concentration"
plural "false"
caps "false"
noprefix "false"
\end_inset
.
\end_layout
\begin_layout Standard
\begin_inset Float figure
wide false
sideways false
status open
\begin_layout Plain Layout
\noindent
\align center
\begin_inset Graphics
filename ../Resources/carrier-density/real-com-carrier-surf-sl5e-12-T300-logCB.png
lyxscale 20
width 80col%
\end_inset
\end_layout
\begin_layout Plain Layout
\noindent
\align center
\begin_inset Graphics
filename ../Resources/carrier-density/im-com-carrier-surf-sl5e-12-T300-logCB.png
lyxscale 20
width 80col%
\end_inset
\end_layout
\begin_layout Plain Layout
\begin_inset Caption Standard
\begin_layout Plain Layout
Complex conductivity over frequency for different carrier densities
\begin_inset CommandInset label
LatexCommand label
name "fig:surf-carrier-concentration"
\end_inset
\end_layout
\end_inset
\end_layout
\end_inset
\end_layout
\begin_layout Subsubsection
Temperature
\end_layout
\begin_layout Standard
Values from 0 to the breakdown temperature of graphene, 2230 K
\begin_inset CommandInset citation
LatexCommand cite
key "graphene-high-temp"
literal "false"
\end_inset
, were varied in order to investigate the effect on conductance.
\end_layout
\begin_layout Standard
\begin_inset Float figure
wide false
sideways false
status open
\begin_layout Plain Layout
\noindent
\align center
\begin_inset Graphics
filename ../Resources/temperature/real-com-temp-surf-sl5e-12-TTF.png
lyxscale 20
width 80col%
\end_inset
\end_layout
\begin_layout Plain Layout
\noindent
\align center
\begin_inset Graphics
filename ../Resources/temperature/im-com-temp-surf-sl5e-12-TTF.png
lyxscale 20
width 80col%
\end_inset
\end_layout
\begin_layout Plain Layout
\begin_inset Caption Standard
\begin_layout Plain Layout
Complex conductivity over frequency for different temperatures
\end_layout
\end_inset
\end_layout
\end_inset
\end_layout
\begin_layout Subsubsection
Scattering Lifetime
\end_layout
\begin_layout Standard
\begin_inset Float figure
wide false
sideways false
status open
\begin_layout Plain Layout
\noindent
\align center
\begin_inset Graphics
filename ../Resources/scatter-lifetime/real-com-SL-surf-300K-TTF10,14.png
lyxscale 20
width 80col%
\end_inset
\end_layout
\begin_layout Plain Layout
\noindent
\align center
\begin_inset Graphics
filename ../Resources/scatter-lifetime/im-com-SL-surf-300K-TTF10,14.png
lyxscale 20
width 80col%
\end_inset
\end_layout
\begin_layout Plain Layout
\begin_inset Caption Standard
\begin_layout Plain Layout
Complex conductivity over frequency for different scattering lifetimes
\end_layout
\end_inset
\end_layout
\end_inset
\end_layout
\begin_layout Subsection
Discussion
\end_layout
\begin_layout Section \begin_layout Section
Conclusion Conclusion
\end_layout \end_layout

7
Resources/README.md Normal file
View File

@ -0,0 +1,7 @@
Surfaces:
35 x 25 x 300 dpi
Lines:
20 x 15 x 300 dpi

Binary file not shown.

After

Width:  |  Height:  |  Size: 1.1 MiB

Binary file not shown.

After

Width:  |  Height:  |  Size: 1.1 MiB

Binary file not shown.

After

Width:  |  Height:  |  Size: 1.2 MiB

Binary file not shown.

After

Width:  |  Height:  |  Size: 1.2 MiB

Binary file not shown.

After

Width:  |  Height:  |  Size: 1.0 MiB

Binary file not shown.

After

Width:  |  Height:  |  Size: 953 KiB

Binary file not shown.

After

Width:  |  Height:  |  Size: 797 KiB

Binary file not shown.

After

Width:  |  Height:  |  Size: 866 KiB

Binary file not shown.

After

Width:  |  Height:  |  Size: 1.2 MiB

Binary file not shown.

After

Width:  |  Height:  |  Size: 1.0 MiB

Binary file not shown.

After

Width:  |  Height:  |  Size: 828 KiB

Binary file not shown.

After

Width:  |  Height:  |  Size: 234 KiB

Binary file not shown.

After

Width:  |  Height:  |  Size: 266 KiB

Binary file not shown.

After

Width:  |  Height:  |  Size: 213 KiB

BIN
Resources/fermi-conc.png Normal file

Binary file not shown.

After

Width:  |  Height:  |  Size: 169 KiB

Binary file not shown.

After

Width:  |  Height:  |  Size: 958 KiB

Binary file not shown.

After

Width:  |  Height:  |  Size: 147 KiB

Binary file not shown.

After

Width:  |  Height:  |  Size: 1.3 MiB

Binary file not shown.

After

Width:  |  Height:  |  Size: 551 KiB

Binary file not shown.

After

Width:  |  Height:  |  Size: 713 KiB

Binary file not shown.

After

Width:  |  Height:  |  Size: 576 KiB

Binary file not shown.

After

Width:  |  Height:  |  Size: 994 KiB

Binary file not shown.

After

Width:  |  Height:  |  Size: 580 KiB

Binary file not shown.

After

Width:  |  Height:  |  Size: 1006 KiB

Binary file not shown.

After

Width:  |  Height:  |  Size: 1011 KiB

Binary file not shown.

After

Width:  |  Height:  |  Size: 691 KiB

Binary file not shown.

After

Width:  |  Height:  |  Size: 1.0 MiB

Binary file not shown.

After

Width:  |  Height:  |  Size: 1.1 MiB

Binary file not shown.

After

Width:  |  Height:  |  Size: 594 KiB