Design and characterization of MoO3/In2Se3 heterojunctions as terahertz/gigahertz band filters suitable for visible light communications and 3G/4G technologies

Abstract

Herein, MoO3/In2Se3 (MI) heterojunctions are fabricated by a vacuum deposition technique for use as wideband filters. The MI devices are composed of optical and electrical parts to detect visible light spectra and microwave ac signals (0.01-3.0 GHz). Basic physical characterizations on the MI devices have shown that the devices are amorphous in nature, composed of MoO2.86/In2Se2.76 and exhibit valence and conduction band offsets of 1.62 eV and 3.10 eV, respectively. The optical conductivity analyses have shown that, the mobility and the plasmon frequency of charge carriers in the MI devices can reach 121.70 cm2/Vs and 5.39 GHz, respectively. The terahertz cutoff frequency in these heterojunctions is in the range of 0.54-4.80 THz. On the other hand, application aimed characterizations has shown that the MI heterojunctions exhibit high photosensitivity against daylight light-emitting-diode irradiation. In addition, imposing ac signal of power of -1.0 dBm and measuring the power transmitted within a band width of 5.0 MHz in the frequency domain of 0.01-3.0 GHz indicated that the MI heterojunction devices can behave as multiband bandstop filters with notch frequency value that suits 3G/4G mobile technologies. The features of the currently proposed MI devices nominate them for use as optical receivers suitable for visible light communication technology and as microwave band stop filters. Keywords: MoO3/In2Se3 heterojunction,band offsets, microwave resonators, terahertz