A Versatile System for Photoconductance Decay Measurement Across a Wide Range of Semiconductor Materials

TL;DR

This paper introduces a versatile, broadband, time-resolved photoconductivity system capable of measuring semiconductor properties across a wide frequency range, with temperature and excitation wavelength flexibility.

Contribution

It presents a novel measurement instrument that extends photoconductivity detection from single-frequency to broadband, enabling comprehensive semiconductor analysis.

Findings

Operates from DC to 100 GHz frequency range

Allows temperature-dependent measurements

Supports multiple photon excitation energies

Abstract

Time-resolved photoconductivity is widely used to characterize non-equilibrium charge-carrier lifetime, impurity content, and solar cell efficiency in a broad range of semiconductors. Most measurements are limited to the detection of reflection of electromagnetic radiation at a single frequency and a single photoexciting light wavelength. We present a time-resolved photoconductivity instrument that enables broadband frequency detection (essentially from DC to 100 GHz), temperature-dependent measurements, and multiple excitation photon energy. The measurement is realized with the help of a coplanar waveguide, which acts as an efficient antenna and whose performance was tested over 10 MHz-10 GHz. The instrument enables the study of surface and bulk charge-recombination specific processes.