Effect of surface preparation on the properties of Au/p-Cd1 xZnxTe

The effect of bromine methanol (BM) etching and NH4F/H2O2 passivation on the Schottky barrier height between Au contact and semiinsulated (SI) p-Cd1 xZnxTe (x 0.09–0.18) was studied through current–voltage (I–V) and capacitance–voltage (C–V) measurements. Nearinfrared (NIR) spectroscopy technique was utilized to determine the Zn concentration. X-ray photoelectron spectroscopy (XPS) for surface composition analysis showed that BM etched sample surface left a Te0-rich layer, however, which was oxidized to TeO2 and the surface [Te]/ ([Cd] + [Zn]) ratio restored near-stoichiometry after NH4F/H2O2 passivation. According to I–V measurement, barrier height was 0.80 0.02– 0.85 0.02 eV for Au/p-Cd1 xZnxTe with BM etching, however, it increased to 0.89 0.02–0.93 0.02 eV with NH4F/H2O2 passivation. Correspondingly, it was about 1.34 0.02–1.43 0.02 eV and 1.41 0.02–1.51 0.02 eV by C–V method