Kinetics of Charge Transport in Wide-Band Semiconductors at the Detection of X-Ray Radiation

TL;DR

This paper develops a kinetic model for charge transport in wide-band semiconductors under X-ray radiation, analyzing charge carrier dynamics and resulting current pulses with analytical solutions for ideal and trap-affected crystals.

Contribution

It introduces a logical framework for modeling X-ray induced conductivity in semiconductors, incorporating spatial charge distribution and trap effects, with analytical current pulse forms.

Findings

Analytical current pulse forms for ideal semiconductors.

Model accounts for deep and shallow traps affecting charge transport.

Provides a basis for interpreting X-ray detection signals.

Abstract

As a result of absorption of X-ray quantum in a semiconductor, the generation of electron-hole pairs takes place in a small volume (diameter < 0.5 mkm). Their surplus energy is lost due to the scattering on phonons of the crystal lattice. Spatial distribution of the charge carriers makes the form of current pulse on electrodes of the crystal complicated when an external electric field is applied. We present a logical chart of construction of basic kinetic model of X-ray conductivity in semiconductors that uses the successive in time calculation of the spatial distribution of free charge arriers and the diffusive-drift model of motion of free carriers in a solid. The basic form of current pulse in an external circle was obtained in the analytical kind for the case of an ideal semiconductor, e.g. that does not contain deep traps and recombination centers, as well as for the case of a crystal with dominant shallow or deep traps of electrons and holes.