A study of the Zn-doping process in metal-organic chemical vapour deposition GaAs and GaAlAs

The incorporation and doping process of impurity Zn in metal-organic chemical vapour deposition GaAs and GaAlAs have been studied using diethylzinc (DEZn) as dopant. It was observed that the Hall concentration increased linearly with an increase in DEZn mole fraction and a reduction of Al composition in the solid phase. The saturation concentration and DEZn distribution coefficients are about 1020 cm−3 and 10–100 for GaAs and about 1019 cm−3 and 1–10 for GaAlAs respectively. A thermodynamic model was used to explain the behaviour of Zn incorporation. On the basis of these results, multilayer heterostructure materials were prepared for photocathodes. The materials obtained in this way have a smooth surface morphology and good interfacial properties.