Gold Schottky contacts on (002) CdSe films growing on p-type silicon wafer

The thermal evaporation technique has been successfully used for depositing CdSe on p-Si (0 0 1) substrates. X-ray diffraction analysis indicated the hexagonal structure for the growing film along the (0 0 2) plane with c-axis perpendicular to Si-substrates. The average particle size was calculated to be similar to 40 nm with a dislocation density at the film surface of 6.25 x 10(10) cm(-2). The temperature dependent electrical properties of Au Schottky contacts to a-plane CdSe thin films growing on p-Si (0 0 1) were investigated over the temperature range of 160-360 K, which show a rectification behavior. The barrier height (phi(b)), and ideality factor (n), values were found to be 0.863 eV at 360 K to 0.451 eV at 160 K, and 2.48 +/- 0.11 at 360 K to 5.18 +/- 0.19 at 160 K, respectively. The increasing of phi(b) while decreasing n with the increase of temperature was described by a double Gaussian distribution with two different regions in the temperature range of 240-360 and 160-240 K. Moreover, it was observed that Au/CdSe/Si/Al heterostructure exhibit space charge limited current (SCLC) at all temperatures. The transition voltage (V-x) from ohmic to SCLC is found to be quite dependent on temperature. The defect levels were estimated from the slope of lnJ versus 1/T plots, which yield two values of activation energies Delta E-d1 = 0.227 +/- 0.011 eV in the 240-360 K range and Delta E-d2 = 0.128 +/- 0.003 eV in the 160-240 K range, respectively. (c) 2012 Elsevier Ltd. All rights reserved.