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 A, c = 15.950 A 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 × 10–3 cm2 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 $$\Phi_{\rm b}$$ 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.