Effect of Au/Ge substrate on the properties of GaSe

Abstract

In this work, the effect of glass/Ge and Au/Ge substrate on the structural, optical and electrical properties of the GaSe thin films is investigated by means of X-ray diffraction, ultraviolet-visible light spectrophotometry and impedance spectroscopy techniques, respectively. While the glass/Ge, glass/GaSe and glass/Ge/GaSe are observed to exhibit amorphous nature of structure, the Au/Ge, and Au/Ge/GaSe are of polycrystalline nature. The formation of the Ge/GaSe interface exhibited high conduction band offset of value of ∼0.90 eV and enhanced the light absorbability of GaSe at 1.47 eV by 80 times. In addition, the modeling of the dielectric spectra for the Ge/GaSe interface revealed optical conductivity parameters presented by scattering time at femtosecond level and improvement of the drift mobility. Moreover, the impedance spectroscopy measurements have shown that with the increasing frequency, the Au/Ge/GaSe/Yb interface exhibit increasing trend of variation in the resistance causing high impedance mode associated with negative capacitance values below 1300 MHz. The effect is completely reversed in the higher range of frequency. These features of the Ge/GaSe interface nominate it as plasmonic interface, microwave cavities and as voltage amplifiers in low power nanoscale devices.