Samples of C-doped GaAs were grown by using solid-source molecular-beam epitaxy, with CBr4 as the C-doping source. A relatively high substrate temperature of 650C was used to induce the formation of di-carbon defects in selected samples. Hall effect, secondary-ion mass spectroscopy and X-ray diffraction measurements were used for sample characterization. By using data obtained from Hall-effect and secondary ion mass spectrometric measurements, calculations were performed of the lattice mismatch which was induced by several possible structures of the di-carbon defect. A comparison of calculated results, with lattice mismatches measured via X-ray diffraction, suggested that the di-carbon defects in compensated GaAs:C samples existed mainly as deep donors and were oriented along the <111> direction.

Di-Carbon Defects in Carbon-Doped GaAs. K.H.Tan, S.F.Yoon, Q.F.Huang, R.Zhang, Z.Z.Sun, J.Jiang, W.Feng, L.H.Lee: Physical Review B, 2003, 67[3], 035208 (5pp)