Yb/Se/WO3/Yb Thin Film Transistors as Rectifiers, N‐Channel Metal Oxide Semiconductor Capacitors, Laser Sensors, and Microwave Bandstop Filters

Abstract

Herein, Yb/p–Se/p–WO3/Yb heterojunctions are employed as multifunctional devices. The devices which show back‐to‐back Schottky (BBS) diode characteristics are prepared by the thermal evaporation method under a vacuum pressure of 10−5 mbar. The structural and morphological analyses on these heterojunctions have shown the growth of amorphous WO3 onto meshed nano/microwire network of hexagonal selenium. The BBS diodes display voltage‐controlled current rectification ratios. In addition, the domination of the thermionic and tunneling current conduction mechanisms in the transistors is computationally investigated. Moreover, studies of the capacitance–voltage characteristic curves demonstrate the performance of the devices as n‐channel metal oxide semiconductor (NMOS) field‐effect transistors responsive in the frequency domain of 1.0–50.0 MHz. Furthermore, the impedance spectroscopy measurements in the frequency domain of 0.01–1.80 GHz indicate the possibility of using the BBS diodes as bandstop filters. The microwave cutoff frequency of these filters reaches 1.06 GHz. On the other hand, when ohmic contacts are formed on the glass/Se/WO3 part using two carbon electrodes, the active layer between the electrodes displays high sensitivity to light irradiations from He–Ne lasers, indicating the possibility of performing as photosensors.