Effect Of Copper Doping Research Articles

Effects of copper doping on the electronic properties of CdS films sintered with CdCl2

Chlorine- and copper-doped polycrystalline CdS films were prepared by coating a slurry which consisted of CdS, CdCl2, CuCl2 and propylene glycol on a glass substrate and sintering in a nitrogen atmosphere, to investigate the effects of copper doping on the window properties of all-polycrystalline CdS/CdTe heterojunction solar cells. The variations of carrier concentration as a function of the amount of copper doping in CdS films which were doped with the order of 1018 cm−3 chlorine have been explained in terms of electronic compensation of the copper impurity. The variations of optical transmission spectra as a function of copper doping have been correlated with the variations of photoconductivity spectra. Even 10 p.p.m. copper in the sintered CdS films degrades the window properties of the CdS films significantly. The degradation is caused by reduced optical transmission rather than by an increase in electrical resistivity.

Charge-Transfer-Controlled Vaporization of Cadmium Sulfide Single Crystals. II. Effect of Copper Doping on the Evaporation Rate of the (0001) Face

The evaporation rate of copper-doped CdS single-crystal c face was measured in the temperature range 680°—740°C. The evaporation rate was decreased markedly with respect to that of the undoped crystals. The copper surface concentration dependence of the vaporization rate was studied by simultaneous diffusion of copper into, and vaporization of the crystal at the (0001̄) and (0001) crystal faces, respectively. The presence of copper impurity in the bulk of the crystal was found to also have an effect on the evaporation rate of CdS. The results were interpreted in terms of self-compensation in CdS via sulfur-vacancy formation, and copper- and sulfur-vacancy diffusion toward the vaporizing surface. Copper doping rendered the crystal vaporization insensitive to light.