Current-transport mechanisms in the Au/GaSe:Nd Schottky contact

Abstract

Structural and electrical features of p-type neodymium-doped GaSe single crystal (0.1 at.% Nd) grown by modified Bridgman technique was investigated through X-ray diffraction (XRD) and current-voltage (I-V) measurements. The XRD spectrum reveals that GaSe:Nd single crystal investigated has hexagonal structure (a = 3.750 angstrom, c = 15.950 angstrom and z = 4, P63/mmc space group) with preferred orientation along (004). Ohmic contact was realized by evaporating indium (In) on one surface of the GaSe:Nd single crystal at 10(-6) Torr while Shottky contact was obtained by evaporating twelve Au dot contacts with 7.85 x 10(-3) cm(2) area on the other surface of the crystal. The I-V characteristics of Au/GaSe:Nd/In Schottky contact was analysed in the 100-360 K temperature range. The main Schottky diode parameters such as ideality factor, barrier height and the series resistance values were determined as a function of temperature using conventional I-V method and Norde method. The ideality factor n of the Au/GaSe:Nd/In Schottky contact was observed to decrease while the barrier height Phi(b) increased with increasing temperature. Temperature dependence of the diode parameters were attributed to the existence of barrier height inhomogeneity by assuming a Gaussian distribution of Au/GaSe:Nd/In Schottky contact.