PREPARATION, AND STRUCTURAL, OPTICAL AND ELECTRICAL-PROPERTIES OF THE CDTE1-XSX SYSTEM

Thin films of the CdTe1-xSx system (0 < x < 1) have been prepared by a thermal evaporation technique, and their structural, optical and electrical properties have been measured in order to characterize the system. Detailed X-ray analysis showed that the structures are polycrystalline and the interplanar distances have been calculated for those systems. The CdTe0.4S0.6 system showed a maximum optical absorption. It is observed that the optical gap, E(opt), is indirect for (0 < x < 0.5) while for (0.6 < x < 1) it is direct. The variation of E(opt) with x in the CdTe1-xSx system is not linear and the minimum value of E(opt) was for x=0.3. The addition of copper dopants up to 3% to the CdTe0.4S0.6 system reduced the value of E(opt). The electrical conductivity showed two values of activation energy indicating different dominant conduction mechanisms in different temperature ranges.