p-TlGaSeS/n-BN heterojunction as a microwave filter and as a photovoltaic device

In this work, a p–n junction made of p-type TlGaSeS and n-type
boron nitride (BN) is investigated and characterized. The
bilayer was studied by means of capacitance–voltage characteristics,
current–voltage characteristics and Bode signal and
photovoltaic effect diagnostics. It was observed that the p-
TlGaSeS/n-BN bilayer exhibits negative capacitance values in
the frequency range of 30–80 MHz. For an ac signal of 30 MHz,
the built-in voltage and density of noncompensating carriers
for the device are found to 1.06 eV and 1.721012 cm3,
respectively. The characteristic Bode curve analysis indicated
that the bilayer behaves as a lowpass microwave filter that
blocks all signals of frequencies larger than 1.28 GHz. The time
constant for this device is 124 ps. In addition, the p-TlGaSeS/
n-BN junction exhibited a well-pronounced photovoltaic
effect. The device showed switching properties from low to
high-current injection at a particular switching voltage. The
switching voltage is sensitive to the light energy and intensity.
It decreased systematically with increasing light intensity
and energy. The device responsivity is 7.64mAW1. The
filtering and photovoltaic properties of the device suggest its
use as an optoelectronic switch and as a microwave filter being
suitable for multipurpose operations.