Effect of anodic growth temperature on native oxides of n-(Hg, Cd)Te

The insulating behavior of anodically grown native oxides on Cd0.23Hg0.77Te can be improved considerably by performing the anodic process at increased temperatures. For the first time, anodic oxides were grown at 50 °C in the standard ethylene glycol-KOH-electrolyte which show a reduction in the high-frequency (1 MHz) conductivity of the order of one magnitude respective to our room-temperature grown oxides. A high electrical breakdown voltage (1.5 MV/cm) and a decreased hysteresis shift (50 mV) underline these results. Other oxide parameters such as fixed oxide charges and fast surface states and the excellent dc resistivity remain practically unchanged. Subroom-temperature grown oxides, however, are extremely unstable.