Gamma irradiation on room temperature short-wavelength HgCdTe photovoltaicdevice studied by admittance spectroscopy

Admittance Spectroscopy (AS) measurements have been performed on n(+)-on-p Hg1-xCdxTe (x = 0.6) photodiodes. Before gamma-irradiation, a deep level lo cated 0.15 eV above the valence band is observed, its trap density N-t = 4. 8 x 10(15) cm(-3) with the capture cross section of approximately 2.2 x 10- 17 cm2, ahich is probably induced by a compound defect correlated with Hg v acancy. After 10(4) Gy gamma-irradiation, a new trap center located 0.19 eV above the valence band is found, and the pre-irradiation trap level 0.15 e V above the valence band is no longer seen. The trap densities for these tw o levels are almost the same. This defect level change ultimately makes the device performance deteriorated.