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

Atef F. Qasrawi, Ahmad Omar and Ala’ M. Azamtta, and Nizami M. Gasanly
Journal Name: 
Physica Status Solidi A: Applications and Materials Science
Pages From: 
Thursday, October 16, 2014
BN, microwave filters, photovoltaics, p–n junctions, TlGaSeS
Supported by AAUJ research deanship through the first cycle I of 2012/2013 & Scientific Research Council at the Ministry of Higher Education of the State of Palestine (project coded 2/1/2013).
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.