Low Temperature Light Induced Change of the Chlorine Center Configuration in CdTe

Abstract

The C1 atoms introduced to CdTe give two kinds of electronic levels. One of them is the simple shallow hydrogenic level observed in the temperature measurements of the Hall coefficient at low temperatures (1). The ionization energy of this level determined from experiment is close to the value predicted by the hydrogenic model. The second level was observed in the pressure measurements of the resistivity and Hall coefficient (2,3). Its energy strongly depends on pressure. Figure 1 shows the effect of the pressure induced deionization of this level on the free electron concentration at temperatures T = 297K, 240K and 186K. From the pressure dependences of the free electron concentration the energy of this level as a function of pressure was calculated. This level is situated above the bottom of the conduction band at ambient pressure (i.e. It is the resonant state) while at 10 kbar it lies over a hundred meV below the bottom of the conduction band.