Fabrication and characterization of TO/GaSe/(Ag, Au) Schottky diodes

Abstract

The optical properties of amorphous GaSe thin films deposited onto tin oxide (TO) coated glass substrates are presented for the purpose of using this material for the fabrication of metal-semiconductor devices. Specifically, the room temperature direct allowed and forbidden transition energy band gaps of glass/TO and glass/TO/GaSe films are estimated and found to exhibit values of 3.95 and 1.95 eV, respectively. The temperature dependence of the energy band gap of the glass/TO/GaSe is also studied in the temperature range of 295 - 450 K by means of optical transmittance and reflectance spectra. This study allowed the identification of the rate of change of the band gap with temperature as -5.0 x 10(-4) eV K-1 and the 0 K energy band gap as 2.1 eV. The above reported optical parameters of the glass/TO/GaSe structure seem to be suitable for semiconductor device production such as solar cell converters, metal - insulator - semiconductor (MIS), metal-oxide-semiconductor (MOS), MOSFET, etc devices. As an application, we have used the glass/TO/GaSe substrate for fabricating Schottky diodes using Ag and Au point contacts. The diodes are characterized by measuring the current (I) - voltage (V) characteristics at room temperature. The I - V curves exhibit rectifying properties. The I-V data analysis in the Schottky region (below 1.0 V) revealed barrier heights of 0.60 and 0.73 eV for Ag and Au point contacts, respectively.