PREPARATION AND SEMICONDUCTIVE PROPERTIES OF ROCK SALT TYPE SOLID-SOLUTION SYSTEMS, CD1-XMXS (M=SR, CA, MG, PB, SN)

Measurements have been made of the semiconductive properties of rock salt type solid solution systems, Cd1-xMxS (M = Sr, Ca, Mg, Pb, Sn) synthezised at high pressures. The Cd1-xCaxS system has a high electrical resistivity of more than 3 × 1010Ω-cm, and a band gap estimated from its optical absorption edge which varies from 1.9-2.6 eV with Cd1-xPbxS system is between 1 and 10Ω-cm, and decreases with increase in the substitution ratio. This system is photoconductive, similar to the normal pressure phase of CdS, and the photoconductivity peak shifts from 0.75-0.96μm with increase in the substitution ratio from 0.1-0.5. The above results are extrapolated to pure CdS and give for CdS having a rock salt type structure high resistivity, photoconductivity, and a band gap of 1.7-1.8 eV at room temperature and normal pressure. © 1979.