Thin films of II–VI compounds and alloys

II–VI semiconductors and their alloys are promising thin film photovoltaic materials. Polycrystalline films of cadmium telluride (CdTe), zinc telluride (ZnTe), cadmium zinc telluride ($\text{Cd}{}_{\mathrm{x}}\text{Zn}{}_{\mathrm{1-x}}\text{Te}$), and mercury zinc telluride ($\text{Hg}{}_{\mathrm{x}}\text{Zn}{}_{\mathrm{1-x}}\text{Te}$) were deposited onto glass and transparent-conducting-semiconductor (TCS) coated glass substrates by metal-organic chemical vapor deposition. Emphasis was directed to the doping of CdTe films, ohmic contacts to p-CdTe, and thin film CdTe homojunctions. CdTe films may be doped intrinsically or extrinsically; gallium and arsenic were used as the extrinsic n and p dopant respectively. p⁺-ZnTe films deposited in situ were used as an ohmic contact to p-CdTe films. Thin film CdTe homojunctions were prepared by the successive in situ deposition of n-CdTe, p-CdTe, and p⁺-ZnTe films on SnO₂-coated glass substrates, and their properties were investigated. The properties of $\text{Cd}{}_{\mathrm{x}}\text{Zn}{}_{\mathrm{1-x}}\text{Te}$ and $\text{Hg}{}_{\mathrm{x}}\text{Zn}{}_{\mathrm{1-x}}\text{Te}$ films with band gap energy in the range 1.65–1.75 eV deposited onto glass and TCS-coated glass substrates were studied.