Barrier height inhomogeneities in Cu-nMoSe₂ Schottky diode

¹ Department of Physical Sciences, P D Patel Institute of Applied Sciences, Charotar University of Science and Technology, Changa 388 421, Gujarat, India
² Department of Physics, Sardar Patel University, Vallabh Vidyanagar 388 120, Gujarat, India

^a e-mail: cksumesh.cv@ecchanga.ac.in

Received: 14 April 2011
Accepted: 5 July 2011
Published online: 28 September 2011

Abstract

The current-voltage characteristics of Cu-nMoSe₂ Schottky diodes measured over a wide temperature range 50 < T <300 K have been interpreted on the basis of thermionic emission mechanism assuming Gaussian barrier distribution. A decrease in the experimental barrier height Φ_b0 and an increase in the ideality factor n with a decrease in temperature have been explained on the basis of barrier height inhomogeneities at the metal-semiconductor interface. It is proven that the presence of a distribution of barrier heights is responsible for the apparent decrease of the zero-bias barrier height. The voltage dependence of the standard deviation causes the increase of ideality factor at low temperatures. The mean barrier height Φ_b0 = 1.05 eV and the Richardson constant A^* = 89.7 A cm⁻² k⁻² have been calculated by means of the modified Richardson plot. The value of the Richardson constant found is much closer than that obtained without considering the inhomogeneous barrier heights with that of the theoretical value.