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Doping evaluation of InP nanowires for tandem junction solar cells

Lindelöw, Fredrik LU (2014) PHYM01 20141
Department of Physics
Solid State Physics
Abstract
In this report, a doping evaluation of MOCVD grown InP nanowires catalysed with nanoimprint defined gold particles have been performed with 4-probe resistivity measurements and spatially resolved Hall measurements. The evaluation is a first step to produce tandem junction nanowire solar cells with nanowires consisting of indium-gallium-phosphide on top of indium-phosphide as an attempt to beat the current world record for nanowire solar cells of 13.8% efficiency. The InP nanowires have been evaluated for both n-doping with TESn and p-doping with DEZn. It is common to optimise doping in nanowires by varying the molar fraction of dopant precursor in the growth chamber, but in this analysis the TMIn flow has been varied while the doping... (More)
In this report, a doping evaluation of MOCVD grown InP nanowires catalysed with nanoimprint defined gold particles have been performed with 4-probe resistivity measurements and spatially resolved Hall measurements. The evaluation is a first step to produce tandem junction nanowire solar cells with nanowires consisting of indium-gallium-phosphide on top of indium-phosphide as an attempt to beat the current world record for nanowire solar cells of 13.8% efficiency. The InP nanowires have been evaluated for both n-doping with TESn and p-doping with DEZn. It is common to optimise doping in nanowires by varying the molar fraction of dopant precursor in the growth chamber, but in this analysis the TMIn flow has been varied while the doping precursor flow have been put to the maximum that the machine can deliver.
The analysis shows that decreasing the molar fraction of TMIn, significantly decreases the resistivity in the n-doped nanowires, which can be interpreted as an increased doping level. In the p-doped nanowires, decreasing the molar fraction of TMIn, slightly increases the resistivity which is opposite to what is seen for n-type InP.
The Hall effect has been measured by contacting single nanowires and measuring the Hall voltage across the nanowire for varied magnetic fields. To accurately determine the doping level, simulations in COMSOL Multiphysics of nanowires with varied doping levels have been used as references. Through comparing the slope of Hall voltage versus magnetic field for both experimental setup and COMSOL simulations, the doping levels were able to be calculated.
High doping levels have been measured in the TESn n-doped InP nanowires (n >1019) but the doping level has not been able to be measured for the DEZn-doped InP nanowires due to high noise level in the Hall measurements for the p-type InP nanowires. (Less)
Please use this url to cite or link to this publication:
author
Lindelöw, Fredrik LU
supervisor
organization
course
PHYM01 20141
year
type
H2 - Master's Degree (Two Years)
subject
keywords
Nanowires, solar cells, doping evaluation, InP, Hall effect
language
English
id
4812407
date added to LUP
2015-02-10 20:55:43
date last changed
2015-02-10 20:55:43
@misc{4812407,
  abstract     = {{In this report, a doping evaluation of MOCVD grown InP nanowires catalysed with nanoimprint defined gold particles have been performed with 4-probe resistivity measurements and spatially resolved Hall measurements. The evaluation is a first step to produce tandem junction nanowire solar cells with nanowires consisting of indium-gallium-phosphide on top of indium-phosphide as an attempt to beat the current world record for nanowire solar cells of 13.8% efficiency. The InP nanowires have been evaluated for both n-doping with TESn and p-doping with DEZn. It is common to optimise doping in nanowires by varying the molar fraction of dopant precursor in the growth chamber, but in this analysis the TMIn flow has been varied while the doping precursor flow have been put to the maximum that the machine can deliver. 
The analysis shows that decreasing the molar fraction of TMIn, significantly decreases the resistivity in the n-doped nanowires, which can be interpreted as an increased doping level. In the p-doped nanowires, decreasing the molar fraction of TMIn, slightly increases the resistivity which is opposite to what is seen for n-type InP. 
The Hall effect has been measured by contacting single nanowires and measuring the Hall voltage across the nanowire for varied magnetic fields. To accurately determine the doping level, simulations in COMSOL Multiphysics of nanowires with varied doping levels have been used as references. Through comparing the slope of Hall voltage versus magnetic field for both experimental setup and COMSOL simulations, the doping levels were able to be calculated. 
High doping levels have been measured in the TESn n-doped InP nanowires (n >1019) but the doping level has not been able to be measured for the DEZn-doped InP nanowires due to high noise level in the Hall measurements for the p-type InP nanowires.}},
  author       = {{Lindelöw, Fredrik}},
  language     = {{eng}},
  note         = {{Student Paper}},
  title        = {{Doping evaluation of InP nanowires for tandem junction solar cells}},
  year         = {{2014}},
}