Performance Evaluation of X-Ray Nanowire Photoconductor Detector

This article describes the use of the SILVACO TCAD device simulator to inspect the electrical performance of a proposed nanowire (NW) X-ray detector. The objective of this work is to obtain a better physical understanding of the behavior of the detector, specifically as a photoconductor
$(\mathrm{n}^{+}-\mathrm{n}-\mathrm{n}^{+})$
type, under different conditions such as flux density, biasing voltage, NW diameter, active region length and temperature. When the length is changed from 1.8
$\mu \mathrm{m}$
to 1.0
$\mu \mathrm{m}$
, the output conductance is changed from 4
$\mu \text{ohm}^{-1}$
to 14
$\mu \text{ohm}^{-1}$
. The simulation results predict the current produced by incident X-ray beams and the gain, while taking into account the relationship between the diameter and energy gap of InP nanowires. The simulation results show that the overall gain is in the range from 10
³
to 10
⁵
when the flux changes from
$2\times 10^{9}$
to
$6.2\times 10^{7}$
Ph/s. The study also models a single semiconductor nanowire and considers the effects of trapping charge and photodoping on the behavior of the nanowire. Additionally, PENELOPE is used to indicate the charge distribution in the InP nanowire material. The simulation results are validated against high-precision measurements, and decent agreement is obtained between the SILVACO TCAD simulation results and experimental results for various beam energies and conditions. This research study provides valuable insights into the functioning of nanowire X-ray detectors.