CHARACTERIZATION OF VERY HIGH-PURITY INAS GROWN USING TRIMETHYLINDIUM AND TERTIARYBUTYLARSINE

The growth of high purity InAs by metalorganic chemical vapor deposition is reported using tertiarybutylarsine and trimethylindium. Specular surfaces were obtained for bulk 5-10 mu m thick InAs growth on GaAs substrates over a wide range of growth conditions by using a two-step growth method involving a low temperature nucleation layer of InAs. Structural characterization was performed using atomic force microscopy and x-ray diffractometry. The transport data are complicated by a competition between bulk conduction and conduction due to a surface accumulation layer with roughly 2-4 x 10(12) cm(-2) carriers. This is clearly demonstrated by the temperature dependent Hall data. Average Hall mobilities as high as 1.2 x 10(5) cm(2)/Vs at 50K are observed in a 10 mu m sample grown at 540 degrees C. Field-dependent Hall measurements indicate that the fitted bulk mobility is much higher for this sample, approximately 1.8 x 10(5) cm(2)/Vs. Samples grown on InAs substrates were measured using high resolution Fourier transform photoluminescence spectroscopy and reveal new excitonic and impurity band emissions in InAs including acceptor bound exciton ''two hole transitions.'' Two distinct shallow acceptor species of unknown chemical identity have been observed.