Effect of gamma ray and high energy oxygen ion radiation on electrical and optical properties of MCT epitaxial layers

Hg1-xCdxTe (0.18<x<0.33) epitaxial layers grown from Te-rich solution have been exposed to Gamma ray radiation upto 650 Grey using Co-60 and high energy oxygen radiation at 100Mev (10(13) ions/cm(2)). The radiation upto 650 Grey using Co electrical resistivity. carrier density and Hall mobility values at 77 K and Infrared (IR) transmission at 300K have been measured in n,p and compensated epilayers both before and after irradiation. These properties am very much affected by these radiations. In the uncompensated p-type and n-type epitaxial layers both types of radiation produced an increase in extrinsic carrier density and a corresponding decrease in Hall mobility. It is observed that both types of radiation have significant effect on the compensated layers and the degree: of compensation is greatly reduced by the oxygen irradiation. The 100 Mev oxygen irradiation produced an apparent shift in the bandgap towards shorter wavelength and the absorption below the energy gap is reduced as shown by FTIR measurements, whereas Gamma ray radiation upto the dose 650 Grey did not have any effect on optical properties. These results show the ability of oxygen radiation to passivate the activity of residual impurities or defects.