Illumination Effects on the Capacitance Spectra and Signal Quality Factor of Al/InSe/C Microwave Sensors

Amorphous indium selenide thin films have been used in the design of a microwave-sensitive Schottky barrier. The illumination effects on the capacitance spectra, on the signal quality factor, and on the capacitance (C)-voltage (V) characteristics of the Al/InSe/C device are investigated. Particular shifts in the amplitude and in the resonance peaks of the capacitance spectra which were studied in the frequency range of 10.0 kHz to 3.0 GHz are observed. While the photoexcitation of these devices increased the capacity level by similar to 1.6 times the original magnitude, the dark quality factor, which was 2.2 x 10(6) at 3.0 GHz, fell to 1.2 x 10(6) when subjected to luminance of 14.7 klux. Analysis of the C-V curves recorded at signal power ranging from wireless local area network (LAN) levels to the maximum output power of third generation (3G) mobiles reflected high tunability of capacitance upon increasing the voltage or power. The tunability of the biased capacitance was much more pronounced in the light than in the dark. The obtained characteristics of the Al/InSe/C sensors indicate their usability in radio and microwave technology.