Metal organic vapor phase epitaxy (MOVPE) grown heterojunction diodes in Hg 1-x Cd x Te

Recent advances in the growth of cadmium mercury telluride (Hg1-xCdxTe or MCT) by metal organic vapor phase epitaxy (MOVPE) allow the fabrication of advanced device structures where both the alloy composition x and the doping concentration can be accurately controlled throughout the epitaxial layer. For p-type doping using arsenic, the acceptor concentration can be varied from 5 X 1015 cm-3 to 4 X 1017 cm-3 and for n-type doping using iodine, the donor concentration can be varied from 1 X 1015 cm-3 to 2 X 1017 cm-3. A number of diode arrays have been fabricated in this material and their properties assessed at 77 K, 195 K and 295 K. It has been found that the diffusion currents are at least ten times lower than in homojunctions. In addition, the devices exhibit negative resistance at temperatures above 190 K due to auger suppression. The successful demonstration of auger suppression in these structures has greatly improved the diode leakage currents at room temperature and will enable the development of new devices such as a room temperature laser detector