would like to acknowledge my supervisor

TESTING SEMICONDUCTOR MATERIALS
USING MICROWAVE TECHNIQUES
Rakshita Ravi
Bachelor of Engineering
Electronic Engineering Major
Department of Electronic Engineering
Macquarie University
September 4, 2017
Supervisor: Dr Nikos Kopidakis

ACKNOWLEDGMENTS
I would like to acknowledge my supervisor, Dr Nikos Kopidakis for the continuous
encouragement and support he has provided throughout my thesis project. I
would like to express my gratitude to my tutor, Affan Baba, for his assistance in
using CST Microwave Studio.

STATEMENT OF CANDIDATE
I, Rakshita Ravi, declare that this report, submitted as part of the requirement for
the award of Bachelor of Engineering in the Department of Electronic Engineering, Macquarie University, is entirely my own work unless otherwise referenced
or acknowledged. This document has not been submitted for qualification or
assessment an any academic institution.
Student’s Name: Rakshita Ravi
Student’s Signature: Rakshita Ravi
Date: 04-09-2017

ABSTRACT
Semiconductor industry is evolving with new emerging semiconductor materials.
Researchers and engineers constantly test and analyse these new materials to
further develop this technology. The most traditional method of testing these
have been through soldering electrical contacts onto the wafer of the material.
However, this is time consuming. TRMC technique used in this thesis is robust
and uses relatively easy setup to analyse electronic properties of the test samples. The experimental setup will use 100 mm brass waveguide with test samples
deposited onto the quartz. This experiment can also be conducted using silver
plated waveguide which is a much better conductor than brass. However, silver
is more expensive and the performance of brass waveguide is very close to silver.
Hallow brass waveguide has power transmission of 99 % and low power reflection and losses. Brass waveguide with quartz has power transmission of 87% and
power reflection of 12%. These results will be used to design the next stages of
the experiment.

Contents
Acknowledgments iii
Abstract vii
Table of Contents ix
List of Figures xi
List of Tables xiii
1 Introduction 1
2 Background 3
2.1 What is TRMC? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.2 Rectangular Waveguide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.3 S Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.3.1 Return Loss and Insertion Loss . . . . . . . . . . . . . . . . . . . . 6
2.4 CST Microwave Studio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3 Testing Semiconductor in Open Waveguide 9
3.1 Waveguide Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.1.1 Material and Length of the waveguide . . . . . . . . . . . . . . . . 9
3.1.2 Waveguide wall thickness . . . . . . . . . . . . . . . . . . . . . . . . 13
3.2 Waveguide with quartz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.2.1 Quartz placement . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
3.3 Waveguide with test sample . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4 Testing Semiconductor in Cavity Resonator 23
5 Conclusions and Future Work 25
6 Abbreviations 27
ix
x CONTENTS
A Consultation form and Project Plan 29
A.1 Consultation Meetings Attendance Form . . . . . . . . . . . . . . . . . . . 29
A.2 Thesis Timeline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Bibliography 31
List of Figures
2.1 Schematic of TRMC technique . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.2 Absorption and Restoration of Microwaves in FP-TRMC . . . . . . . . . . 4
2.3 Schematic of 2-port S-parameter model . . . . . . . . . . . . . . . . . . . . 6
3.1 Hallow waveguide model . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.2 TM10 Field Distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.3 S-Parameters graph from 50 mm brass waveguide . . . . . . . . . . . . . . 12
3.4 Power Transmission in Brass and Silver waveguide . . . . . . . . . . . . . . 13
3.5 Power Transmission vs Wall Thickness . . . . . . . . . . . . . . . . . . . . 15
3.6 Brass waveguide with quartz . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3.7 Effect of Quartz on Field Distribution . . . . . . . . . . . . . . . . . . . . . 17
3.8 Power Transmission in Brass waveguide with quartz . . . . . . . . . . . . . 18
3.9 Power Reflection in Brass waveguide with quartz . . . . . . . . . . . . . . . 19
3.10 Power Absorption in Brass waveguide with quartz . . . . . . . . . . . . . . 19
3.11 Power Transmission with different quartz position . . . . . . . . . . . . . . 20
3.12 Power Reflection with different quartz position . . . . . . . . . . . . . . . . 21
3.13 Power Absorption with different quartz position . . . . . . . . . . . . . . . 21
A.1 Consultation form . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
A.2 Gantt Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
xi

List of Tables
2.1 TE
m;n mode cutoff frequencies . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2 TM
m;n mode cutoff frequencies . . . . . . . . . . . . . . . . . . . . . . . . 5
3.1 Brass Hallow Waveguide . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.2 Silver Hallow Waveguide . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.3 100mm Brass Hallow Waveguide . . . . . . . . . . . . . . . . . . . . . . . . 14
3.4 Brass Waveguide with Quartz . . . . . . . . . . . . . . . . . . . . . . . . . 18
3.5 100 mm Brass Waveguide with varying quartz position . . . . . . . . . . . 20
xiii

Chapter 1
Introduction
Semiconductors dominate the modern-day electronics, they are an essential substance
in electronic devices such as solar cells, LEDs, mobile phones, computers, and more.
The unique atomic structure of the semiconductor allows the conductivity to be easily
controlled. Conductivity in a semiconductor can be stimulated by electric currents or electromagnetic fields. This conduction however varies depending on the amount of electric
currents supplied or by the frequency and the intensity of the EM waves.
The sheer popularity and high demand of semiconductors in modern world and has
led to new organic and inorganic semiconductor materials to emerge in this industry.
This has led to the requirement of a reliable and efficient testing technique to probe
these new materials for their electronics properties. This will assist in future development
of semiconductor technology. Semiconductor materials have been tested previously by
others using various methods. The most popular method has been through soldering
metal electrical contacts onto the wafer of the material. The main disadvantage of using
this method is that it is time consuming and requires personnel with good skill.
This thesis uses an alternative method which is relatively easy and robust to test
conductivity in semiconductors. This is achieved through Time Resolved Microwave Conductivity (TRMC). TRMC is a contactless conductivity probing technique, which involves
measuring the transmission of microwave signal through the sample as a function of time
delay between pump pulse and microwave probe pulse.
Experiments will be conducted using computer simulation technology (CST) and the
results obtained from these experiments are valuable and play a significant role in prototyping. In the actual experimental setup (prototype), the only results TRMC can provide
are quantitative results such as the amount of power absorbed, reflected and transmitted
by the sample and then these results are used to translate it to the samples electronic
properties. The simulation results obtained in this thesis provides quantitative results
as well as qualitative results. For instance, qualitative results provide a greater understanding of how electrical and magnetic fields interact with the sample. These simulation
results assist in designing the experiment in a better way. These simulation results can
indicate if this experimental technique can measure low conductivity materials or just
high conductivity materials, if it can probe just photoconductivity materials or can it
1
2 Chapter 1. Introduction
also measure dark conductivity materials.
Chapter 2
Background
2.1 What is TRMC?
TRMC technique was first used by Margenau in mid-40s to analyze the behavior of
charged particles in their gaseous form. This became popular after Warman and De Haas
introduced PR-TRMC technique and then later evolved to FP-TRMC (Flash Photolysis
Time Resolved Microwave Conductivity) in early 80s, where laser light was used as the
radiation source. The TRMC technique setup is displayed in Figure 2.1. The sinusoidal
lines in the figure represent the standing-wave pattern of the microwave electric fields.
Notice, sample is placed at a position where there is maximum electric field strength
inside the cavity.
Figure 2.1: Schematic of TRMC technique setup using microwave cavity resonator and
sample. [1]
In FP-TRMC, the sample is placed inside a cavity resonator at position of maximum
electric field strength such that when microwaves is applied to the sample, and the light
is flashed (pumped) on the material, the photo induced carriers within the sample are
excited and absorbs particular range of frequencies. When the light is turned-off, then
the carriers return to their stable state, restoring the microwave intensity. This process
is better illustrated in Figure 2.2. In Figure 2.2 A, microwaves (probe) is applied to
3
4 Chapter 2. Background
the sample. Figure 2.2 B, Light is pumped onto the sample, and the carrier charges are
exited. Microwave intensity is reduced while leaving the sample. Figure 2.2 C, Light is
turned-off, the carrier charges are returning back to their normal state (very few mobile
charges present), and microwave intensity is restored. [2] [3]
Figure 2.2: Absorption and Restoration of Microwaves in FP-TRMC. [3]
The restoration of microwave takes place over a certain period of time. Hence the
term time-resolved. The absorption and the restoration of the waves indicate a lot about
the properties of the material and in particular about its conductivity. In simple terms,
and to a certain extent, the change in absorbed microwave power is proportional to the
change in conductivity of the sample.
The main advantage of using FP-TRMC technique is that, it is guaranteed that the
number of mobile electrons created in the semiconductors conduction band is related to
its change in conductivity. FP-TRMC can be used to monitor the generation of charge
carriers in thin films and in particular it is very useful in determining the key parameters
of the photoactive part of the photovoltaic device. [4]
2.2 Rectangular Waveguide
Rectangular waveguides are one of the earliest and well know technology used to transport
microwave signals with their frequency band ranging from 1GHz to over 220 GHz. Since
waveguide is basically a metal pipe, it has electric and magnetic field perpendicular to the
direction of travelling waves. Waveguides have certain boundary conditions that restrict
the propagation mode.
• The electric field must be orthogonal to the conductor in order to exist at the surface
of that conductor.
• The magnetic field must not be orthogonal to the surface of the waveguide.
Due to these boundary conditions, waveguides have transverse electric (TE) and transverse magnetic (TM) modes for propagation. Transverse electric (TE) and Transverse
magnetic (TM) have different field configurations and each of these configuration is known
2.3 S Parameters 5
as a mode. A simple notation can be used to describe various modes of propagation as
shown below:
Tx
m;n (1)
where
x = E for transverse electric mode, and M refers to transverse magnetic mode
m = the number of half-wavelengths along the x axis
n = the number of half-wavelengths along the y axis
TE wave has Ex, Ey, Hx, Hy, and Hz components. TM wave has Ex, Ey, Ez, Hx
and H
y components. Signal propagation in a waveguide depends on the frequency of the
input signal. EM waves propagate inside the waveguide only when the frequency of the
applied signal is higher than the cut-off frequency fc;mn. [5] [6]
fc;mn = 1
2πpµrmπ a )2nπ b )2 m; n = 0; 1; 2; ::: (2)
Table 2.1: TE
m;n mode cutoff frequencies

m	n	fc;mnGHz
1 2 0 1	0 0 1 1	6.562 13.123 14.764 16.156

Table 2.2: TM
m;n mode cutoff frequencies

m	n	fc;mn GHz
1 1 2	1 2 1	16.156 30.248 19.753

WR90 is metallic X band rectangular waveguide and its cross-sectional dimensions are
a=22.86 mm and b=10.16 mm. X-band region has frequencies from 8 GHz to 12.5 GHz
and the Table 2.1 and 2.2 above indicate that WR90 allows TE10 mode to propagate in
the waveguide and this is also the dominant mode.
2.3 S Parameters
Scattering parameters or S parameters define the input output relationship between the
device ports.
Applying the figure 2.3 to this thesis, the source is on Port 1 and detection is on Port
2. This way a1 is the incident power, b1 is the reflected power, b2 is the transmitted
6 Chapter 2. Background
Figure 2.3: Schematic of 2-port S-parameter model. [7]
power and a2 on the Port 2 will be eliminated (i.e. a2 = 0). This eliminates the S12 and
S22 parameters leaving behind just S11 and S21. Now S11 can be considered as the input
reflection coefficient and S21 as transmission coefficient. [8] [9]
The equations below represent S11 and S21 in terms of incident energy (Ei), reflected
energy (Er) and transmitted energy (Et).

S11 = 20log10 Ei dB Ei dB	(3)
(4)

Er
S21 = 20log10 Et
2.3.1 Return Loss and Insertion Loss
Return loss (RL) is a measure of effectiveness of delivering power from source (Port 1) to
load. Return loss is a positive quantity when reflected power PR is less than PI. RL
is the difference in dB between input power PI, and reflected power PR. Insertion
Loss is the loss of signal power during signal transmission and similar RL, IL is a positive
quantity. The below equations represent RL and IL in terms of input power PI, reflected
power PR and transmitted power PT . [10]
RL = 10log10PPRI dB (5)
IL = 10log10PPTI dB (6)
RL and S11 can be easily converted to one another. This relationship holds between
IL and S21. [11]

S11 = 20log10 Ei dB = 10log10 Ei dB = 10log10PI dB	(7)
Er	Er	PR

2
Therefore, RL dB = -S11 dB and IL dB = -S21 dB
2.4 CST Microwave Studio 7
S11 = 10log10PPRI dB (8)
S21 = 10log10PPTI dB (9)
2.4 CST Microwave Studio
CST Studio Suite is a simulation platform for electromagnetic (EM) field problems and
related applications. They currently offer seven modules namely, CST Microwave Studio,
CST EM Studio, CST Particle Studio, CST Design Studio, CST PCB Studio, CST Cable
Studio and CST MPhysics Studio. This thesis uses CST Microwave Studio which is
used for EM design, simulation and analysis of high frequency problems. This studio
is capable of analysing components such as single and multi-element antennas, filters,
waveguides, resonators and many more. This module offers a range of solvers that can
be used depending on the application and hence, this studio can solve basically any high
frequency field problem. In this thesis, the experimental setup is quite simple with basic
structure and time domain solver is sufficient to simulate this structure. Time domain
solver relies on Maxwells equations when simulating the structure and it provides real
time domain simulations which are extremely useful when studying the field propagation
through a component. [12]
8 Chapter 2. Background
Chapter 3
Testing Semiconductor in Open
Waveguide
Rectangular Waveguide modelled in CST is a replicate of WR90 waveguide available in
store. Before directly testing the semiconductor samples, initial testing was performed
on just waveguides. This was done to check the effectiveness of microwave propagation
within the waveguide. Numerous experimental setups and model configurations were
investigated to find the best suitable configuration which would deliver the most reliable,
accurate and desirable results. Much time was dedicated for these initial stages because
it is crucial to get them right as the later stages of this thesis are heavily dependent on
these experimental setup.
3.1 Waveguide Configurations
A number of factors can affect the microwave propagation within the waveguide, however
the major factors include the material of the waveguide, length of the waveguide, and the
wall thickness of the waveguide.
3.1.1 Material and Length of the waveguide
Waveguide model specifications
• Inner Dimensions: a = 22.86 mm, b = 10.16 mm
• Length of the waveguide (z axis): 50 mm, 100 mm and 150 mm
• Wall thickness: 0.5 mm
• Material of the waveguide: Brass (91%) and Silver.
• Material inside the waveguide: Vacuum
• Input Power (PI) = 0.5W
9
10 Chapter 3. Testing Semiconductor in Open Waveguide
Figure 3.1 displays the models of brass and silver waveguides along with their material
configurations. These models are simulated using T solver. T solver provides numerous
1D, 2D/3D results, however the results that are of interest for this thesis are the E-field
and H-field distribution, and S-parameters.
(a) Brass Waveguide
(b) Silver Waveguide
Figure 3.1: Hallow waveguide model
Field Distributions
The E-field and H-field distribution in figure 3.2 are obtained from brass model in figure
3.1a. These field distributions indicate that waveguide is in TE10 mode and these results
support the concept discussed in background chapter.
3.1 Waveguide Configurations 11
(a) E-field cross-section 1 (b) H-field cross-section 1
(c) E-field cross-section 2 (d) H-field cross-section 2
(e) E-field cross-section 3 (f) H-field cross-section 3
Figure 3.2: TM10 Field Distribution
12 Chapter 3. Testing Semiconductor in Open Waveguide
S Parameters
S parameters (S11 and S21) values obtained from each waveguide can be used to calculate
reflected power and transmitted power. This is achieved by rearranging the equations
(8), (9) to obtain equation (10), (11). Table 3.1 and 3.2 are derived by substituting
S-parameters at 9 GHz into equation (10) – (12).
PR = 10( S10 11 ) × PI (10)
PT = 10( S10 21 ) × PI (11)
PL = PI – (PR + PT ) (12)
Figure 3.3: S-Parameters graph from 50 mm brass waveguide
Table 3.1: Brass Hallow Waveguide

Length(mm)	S11(dB)	S21(dB)	PR (W)	PT (W)	PT %	PR %	PL
50 100 150	-81.609 -80.987 -81.106	-0.007 -0.017 -0.033	3.45E-09 3.98E-09 3.87E-09	0.499 0.498 0.496	99.83 99.6 99.2	6.9E-07 7.9E-07 7.7E-07	0.0008 0.0019 0.0038

Table 3.2: Silver Hallow Waveguide

Length(mm)	S11(dB)	S21(dB)	PR (W)	PT (W)	PT %	PR %	PL
50 100 150	-85.229 -84.596 -84.706	-0.004 -0.011 -0.024	1.49E-09 1.73E-09 1.69E-09	0.499 0.498 0.497	99.89 99.7 99.4	2.9E-07 3.4E-07 3.38E-07	0.0005 0.0013 0.0027

Waveguides are predominately made from brass as it is relatively cheap, but waveguides also come with silver plating which reduces the resistance loss and increases the
3.1 Waveguide Configurations 13
Figure 3.4: Power Transmission in Brass and Silver waveguide with varying lengths
waveguide efficiency. However, waveguides with silver plating is expensive. The results
from figure 3.4 indicates that silver is slightly better than brass waveguide. The difference between silver and brass power transmission is less than 0.2% and upgrading a brass
waveguide to a silver plated waveguide is not worth it for such small difference.
The figure 3.4 also indicates that the percentage of power transmission is reduced as
the length of the waveguide is increased. Since neither brass or silver are perfect metals,
instead they are lossy metals and the waveguide is not infinitely long, this results in
power losses and reflection during microwave propagation. At this stage, a 100 mm brass
waveguide will be suitable for this thesis.
3.1.2 Waveguide wall thickness
Wall thickness of the waveguide depends on the skin depth of the material. The skin
depth of brass material at 9 GHz frequency is as following
δS = r!µσ 2 = rπfµ 1 oσ (13)
Where:
µo = Permeability = 4π × 10-7
σ = Conductivity of metal (Brass) = 2:56 × 107
14 Chapter 3. Testing Semiconductor in Open Waveguide
f = 9 GHz
Therefore, from equation (13), δS = 1µm
Waveguide model specifications
• Inner Dimensions: a = 22.86 mm, b = 10.16 mm
• Length of the waveguide (z axis): 150 mm
• Wall thickness: 0.5 mm, 1 mm and 1.5 mm
• Material of the waveguide: Brass (91%) lossy metal
• Material inside the waveguide: Vacuum
• Input Power (PI) = 0.5 W
Table 3.3: 100mm Brass Hallow Waveguide

Wall Thickness(mm)	S11(dB)	S21(dB)	PR (W)	PT (W)	PT %	PR %	PL
0.5 1 1.5	-81.106 -81.055 -81.041	-0.033 -0.031 -0.032	3.87E-09 3.92E-09 3.93-09	0.496 0.496 0.496	99.23 99.26 99.26	7.75E-07 7.84E-07 7.86E-07	0.0038 0.0036 0.0036

Figure 3.5 indicates that PT at 0.5 mm wall thickness is less than PT at 1 mm. This
suggests that at lower wall thickness, there is still a bit of field leakage from walls of the
waveguide. At 1 mm, PT reaches its peak and at 1.5 mm, the curve dips slightly which
could be due to resonance. Regardless of these minorities, PT remains at 99 % for wall
thickness between 0.5 mm and 1.5 mm. This 1 % of power loss is due to brass not being
a perfect metal and the waveguide walls are not infinitely thick.
3.2 Waveguide with quartz 15
Figure 3.5: Power Transmission in Brass waveguide with varying wall thickness
3.2 Waveguide with quartz
Quartz plays an important role throughout this thesis even though it is not an object
of interest. Semiconductor material (object of interest) is deposited on a piece of quartz
before placing it in the waveguide or cavity. To keep the experiment controlled, quartz is
tested and analyzed for its microwave absorption before depositing semiconductor materials on it. This helps in differentiating the amount of microwaves absorbed by the quartz
and by the semiconductor material at the final stage. Figure 3.6 shows 100 mm brass
waveguide model with quartz at 50 mm (i.e. half way through the waveguide).
Power absorption can be found by subtracting the power loss of hallow waveguide PL
(hallow) from power loss of waveguide with quartz PL (quartz) and this can be seen
in equation (13)
PA = PL(quartz) – PL(hallow) (14)
Waveguide model specifications
• Inner Dimensions: a = 22.86 mm, b = 10.16 mm
• Length of the waveguide (z axis): 100 mm
16 Chapter 3. Testing Semiconductor in Open Waveguide
• Wall thickness: 0.5 mm
• Material of the waveguide: Brass (91%) lossy metal
• Material inside the waveguide: Vacuum
• Input Power (PI) = 0.5 W
Quartz specifications
• Inner Dimensions: a = 22.86 mm, b = 10.16 mm
• Quartz thickness: 1 mm
• Quartz placement (on z axis): 50 mm
• Material: Quartz (lossy)
Figure 3.6: Brass waveguide with quartz placed at 50 mm on z axis
Field Distributions
Figure 3.7 shows the field distributions for waveguide model with and without quartz. In
these models, the quartz is placed in the middle of the waveguide and the effect quartz
has on field distribution is clearly visible and highlighted in figures 3.7 a and b. Notice,
E-field and H-field are higher for quartz on input side (Port 1) as supposed to hallow
waveguides. This is due to the reflected waves being in phase with the incident waves
which causes the resulting fields to be amplified near port 1.
3.2 Waveguide with quartz 17
(a) E-field with quartz (b) H-field with quartz
(c) E-field without quartz (d) H-field without quartz
Figure 3.7: Effect of Quartz on Field Distribution
18 Chapter 3. Testing Semiconductor in Open Waveguide
S Parameters
Until now, there was only one material inside the hallow waveguide, which was vacuum.
But now, microwaves have to travel through vacuum as well as quartz which are two very
different medium and have different refractive index. The change in medium causes the
microwaves to be reflected, absorbed and transmitted. The amount of power transmitted,
reflected and absorbed can be seen in figures 3.8 to 3.10.
The presence of quartz has a great impact on power transmission and reflection as
shown in figure 3.8 and 3.9. Quartz increases the power reflection by 12% as compared
to power reflection in hallow waveguide. Figure 3.10 indicates that absorption in quartz
is extremely low, and power loss is the major contributor to the difference between power
transmission and power reflection.
Table 3.4: Brass Waveguide with Quartz

Length(mm)	S11(dB)	S21(dB)	PR (W)	PT (W)	PL (W)	PA (W)
50 100 150	-9.1623 -9.1488 -9.1563	-0.57 -0.58 -0.60	0.0606 0.0608 0.0607	0.438 0.436 0.435	0.001 0.002 0.004	0.000179 0.000178 0.000331

Figure 3.8: Power Transmission in Brass waveguide with and without quartz
3.2 Waveguide with quartz 19
Figure 3.9: Power Reflection in Brass waveguide with and without quartz
Figure 3.10: Power Absorption in Brass waveguide with and without quartz
3.2.1 Quartz placement
Position of quartz within the waveguide is one of the factors that needs to be investigated.
Power transmission, absorption and reflection was investigated by varying the quartz
position within the waveguide as shown in table 3.5.
Figure 3.11 to 3.13 indicate that position of the quartz in an open waveguide does
not have a massive impact on power transmission or reflection as they are approximately
87.4% and 12.1% respectively. However, power absorption is high when quartz is placed
closer to port 2 rather than port 1. Since power absorption is found from power loss (refer
to equation (14)) and port 1 is the input port, there is more power reflection rather than
power loss. However, as microwaves travel through waveguide towards port 2, there will
be some losses along the way. The angle at the which microwaves hit the quartz also
plays an important role in determining the amount of power reflected and absorbed by
the quartz. Notice how power absorption is negative for quartz positioned at 25 mm, this
20 Chapter 3. Testing Semiconductor in Open Waveguide
is because, power loss in this model is lower than the power loss in the hallow waveguide.
Table 3.5: 100 mm Brass Waveguide with varying quartz position

Position(mm)	S11(dB)	S21(dB)	PR (W)	PT (W)	PL (W)	PA (W)
25 50 75	-9.145 -9.148 -9.172	-0.583 -0.584 -0.583	0.0608 0.0608 0.0604	0.437 0.436 0.437	0.0020 0.0021 0.0024	-0.0001 4.2E-10 0.00023

Figure 3.11: Power Transmission with different quartz position
3.2 Waveguide with quartz 21
Figure 3.12: Power Reflection with different quartz position
Figure 3.13: Power Absorption with different quartz position
22 Chapter 3. Testing Semiconductor in Open Waveguide
3.3 Waveguide with test sample
This section will include test samples with different electrical properties deposited on top
of quartz and then these test sample will be analysed for their PT, PR and PA. The results
obtained in pervious sections will be used to design next stage of this thesis.
Chapter 4
Testing Semiconductor in Cavity
Resonator
23
24 Chapter 4. Testing Semiconductor in Cavity Resonator
Chapter 5
Conclusions and Future Work
No conclusion can be drawn at this stage apart from the fact that the next following
experimental procedures will be carried out using 100 mm brass waveguide with a 1 mm
thick quartz.
25

Chapter 6
Abbreviations

TRMC FP-TRMC CST	Time Resolved Microwave Conductivity Flash Photolysis Time Resolved Microwave Conductivity Computer simulation technology
TE	Transverse Electric mode
TM	Transverse Magnetic mode
EM waves E-field H-field RL	Electromagnetic waves Electric field Magnetic field Return loss
IL	Insertion loss
PI	Input Power
PR	Reflected Power
PT	Transmitted Power
PA	Absorbed Power

27
28 Chapter 6. Abbreviations
Appendix A
Consultation form and Project Plan
A.1 Consultation Meetings Attendance Form
29
30 Chapter A. Consultation form and Project Plan
Figure A.1: Consultation Form
A.2 Thesis Timeline 31
A.2 Thesis Timeline
32 Chapter A. Consultation form and Project Plan
Figure A.2: Gantt Chart
Bibliography
[1] O. Ostroverkhova, Handbook of Organic Materials for Optical and (Opto)Electronic
Devices, 1st ed. Woodhead Publishing, 2013.

[2] R. Paschotta. Pump-probe measurements. [Online]. Available: rp-photonics.com/pump probe measurements.html

https://www.

[3] NREL. Probing solar photo conversion using flashphotolysis timeresolved microwave
conductivity. [Online]. Available: https://energysciences.nrel.gov/sites/default/files/
embedded/files/fp trmc training 1.pdf
[4] J. E. Kroeze, Photoinduced Charge Separation In Dye-Sensitized Films Of Smooth
and Nanocrystalline Tio2. The Netherlands: DUP Science, 2004.
[5] N. R. Council, Microwave Processing of Materials. Washington, DC: The National
Academies Press, 1994.
[6] J. J. Carr, Practical Antenna Handbook, 4th ed. McGraw-Hill, 2001.
[7] R. WIreless. Vector network analyzer tutorial | vna tu

torial.	[Online].	Available:	http://www.rfwireless-world.com/Tutorials/
Vector-Network-Analyzer-VNA-tutorial.html [8] Y. Fujishiro. Taking advantage of s-parameter. [Online]. Available: //product.tdk.com/en/products/emc/guidebook/eemc basic 03.pdf	https:

[9] D. M. Pozar, Microwave Engineering, 3rd ed. John Wiley, 2005.
[10] T. Bird, Definition and Misuse of Return Loss, journal =.”
[11] M. Hyde. What is the difference between returnloss(db) and s11(db).
[Online]. Available: https://www.researchgate.net/post/What is the difference
between ReturnlossdB and S11dB
[12] C. Studio. Cst micorwave studio | transient solver. [Online]. Available:
https://www.cst.com/products/cstmws/solvers/transientsolver
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