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Scanning Probe Microscopy Conductivity Measurements of InP Nanowires for Solar cells

Irfan, Mubashar LU (2013) FYSM31 20131
Synchrotron Radiation Research
Department of Physics
Abstract
This thesis is devoted to the analysis of the I-V properties of axial InP pn-junction nanowires made for solar cell application. A novel method has been used to measure the I-V characteristics very accurately and reproducibly, using scanning tunneling microscopy (STM). The STM is used to first image the nanowires from top and then form a low resistive point contact between the STM tip and an individual nanowire, which is still on its growth substrate, in ultrahigh vacuum conditions. This setup is well suited to investigate the I-V characteristics of individual nanowires with high accuracy and statistical relevance.
In particular, the I-V curves are first analyzed to evaluate when a low resistive point contact has been established. Then,... (More)
This thesis is devoted to the analysis of the I-V properties of axial InP pn-junction nanowires made for solar cell application. A novel method has been used to measure the I-V characteristics very accurately and reproducibly, using scanning tunneling microscopy (STM). The STM is used to first image the nanowires from top and then form a low resistive point contact between the STM tip and an individual nanowire, which is still on its growth substrate, in ultrahigh vacuum conditions. This setup is well suited to investigate the I-V characteristics of individual nanowires with high accuracy and statistical relevance.
In particular, the I-V curves are first analyzed to evaluate when a low resistive point contact has been established. Then, I-V characteristics of nanowires before and after sample cleaning are obtained in order to compare the effect of the surface oxide layer on the nanowire electric properties. The InP pn-junction nanowires show rectifying behavior with typical ideality factors between 2.5 and 2.6. When the surface oxide is removed from the nanowires by annealing under atomic hydrogen background, the ideality factor slightly improves and the conductivity of the individual nanowires increases dramatically for both reverse and forward bias. (Less)
Please use this url to cite or link to this publication:
author
Irfan, Mubashar LU
supervisor
organization
course
FYSM31 20131
year
type
H2 - Master's Degree (Two Years)
subject
keywords
Nanowire, Semicondutor, Solar energy, Photovoltaic
language
English
id
3559203
date added to LUP
2013-03-07 19:53:22
date last changed
2013-03-07 19:53:22
@misc{3559203,
  abstract     = {This thesis is devoted to the analysis of the I-V properties of axial InP pn-junction nanowires made for solar cell application. A novel method has been used to measure the I-V characteristics very accurately and reproducibly, using scanning tunneling microscopy (STM). The STM is used to first image the nanowires from top and then form a low resistive point contact between the STM tip and an individual nanowire, which is still on its growth substrate, in ultrahigh vacuum conditions. This setup is well suited to investigate the I-V characteristics of individual nanowires with high accuracy and statistical relevance.
In particular, the I-V curves are first analyzed to evaluate when a low resistive point contact has been established. Then, I-V characteristics of nanowires before and after sample cleaning are obtained in order to compare the effect of the surface oxide layer on the nanowire electric properties. The InP pn-junction nanowires show rectifying behavior with typical ideality factors between 2.5 and 2.6. When the surface oxide is removed from the nanowires by annealing under atomic hydrogen background, the ideality factor slightly improves and the conductivity of the individual nanowires increases dramatically for both reverse and forward bias.},
  author       = {Irfan, Mubashar},
  keyword      = {Nanowire,Semicondutor,Solar energy,Photovoltaic},
  language     = {eng},
  note         = {Student Paper},
  title        = {Scanning Probe Microscopy Conductivity Measurements of InP Nanowires for Solar cells},
  year         = {2013},
}