Residual impurities in high purity GaAs layers grown by liquid phase epitaxy in H_2-Ar atomsphere

摘要

We have carried out LPE of GaAs using Ga as a solvent in high purity Ar and its mixutre with H_. The quality of the layers was compared with that grown in pure H_2. The layers grown in Ar showd n-type conductivity. Net carrier concentrationa nd mobility were 3×10~14 cm~-3 and 4×10~4 cm~2 V~-1 S~-1 at 77 K which is comparable to that for the layers grown in H_2. Photoluminescence measurements reveal that Si is the main acceptor impruity in GaAs layers which were grown in H_2 atmoshpere. In contrast, C is the main impurity in the layers grown in Ar atomsphere. The impurity incorporation into GaAs layers can be ascribed to the chemicla reactions that take place during the LPE process in the growth system which consists of quartz reactor tube, graphite crucible, and Ga solvent.