Abstract
In-phase and in-quadrature frequency-resolved photocurrent (IP-FRPC and IQ-FRPC) measurements in amorphous (a-) Ge
and a-GeSi thin films are reported as a function of excitation light intensity, wavelength, and applied dc electric field at room
temperature. These measurements provide the carrier lifetime distributions directly. The in-quadrature signal is much more
sensitive to phase inaccuracies than the in-phase signal. The lifetime of a-Ge and a-GeSi is found to be independent of
excitation light intensity and applied electric field. We also present the exponent in the power-low relationship,
,
between light generation flux and photocurrent at different frequencies and wavelengths. It is found that the exponent, ,
has a sublinear intensity dependence with 0.55 0.90. The exponent was also compared for IP-FRPC and IQ-FRPC
outputs, and different materials, which supply information about recombination kinetics. The results are discussed on the
basis of models proposed for the photocurrent studies.
Keywords
a-Ge and a-SiGe thin films, IP-FRPC and IQ-FRPC responses, Photocarrier lifetime, Intensity- and wavelength- dependence.
Citation
R. KAPLAN, B. KAPLAN, Frequency-resolved photocurrent studies in amorphous germanium, Optoelectronics and Advanced Materials - Rapid Communications, 18, 1-2, January-February 2024, pp.76-82 (2024).
Submitted at: June 9, 2022
Accepted at: Feb. 9, 2024