Design and Applications of Yb/Ga<sub>2< Schottky Barriers

Abstract

In this paper, the Ga2Se3 crystals are used to design a Yb/Ga2Se3/C Schottky barrier. The device structure is investigated by the X-ray diffraction technique, which reveals a monoclinic-face-centered cubic interfacing type of structure. The barrier is studied by means of current (I)-voltage (V) characteristics in the dark and under light through photoexcitation from tungsten lamp and from the He-Ne laser. In addition, the impedance spectroscopy of these devices is studied in the frequency range of 10-1400 MHz. The photoexcited I-V curve analysis allowed investigating the biasing voltage, illumination power, and energy effects on the diode physical parameters, which are presented by the rectification ratio, the Schottky barrier height, the ideality factor, the series resistance, the photosensitivity, the responsivity, and the external quantum efficiency (EQE). While a maximum photosensitivity of 42 was observed for laser excitation with a wavelength of 632 nm at a reverse bias of 4.4 V, the EQE reached value of 1652% at 19.0 V. On the other hand, the ac current conduction analysis of the electrical conductivity, which was determined from the impedance spectral analysis, indicated that the ac signal processing through the Yb/Ga2Se3/C samples is due to the correlated hopping conduction through localized states of Fermi density of 3.98 x 10(19) eV(-1) cm(-3). The high-and biasing-dependent EQE% nominates the Yb/Ga2Se3/C as a tunable optoelectronic device.