CHARACTERIZATION OF VERY HIGH-PURITY INAS GROWN USING TRIMETHYLINDIUMAND TERTIARYBUTYLARSINE

The growth of high purity InAs by metalorganic chemical vapor depositi on is reported using tertiarybutylarsine and trimethylindium. Specular surfaces were obtained for bulk 5-10 mu m thick InAs growth on GaAs s ubstrates over a wide range of growth conditions by using a two-step g rowth method involving a low temperature nucleation layer of InAs. Str uctural characterization was performed using atomic force microscopy a nd x-ray diffractometry. The transport data are complicated by a compe tition between bulk conduction and conduction due to a surface accumul ation layer with roughly 2-4 x 10(12) cm(-2) carriers. This is clearly demonstrated by the temperature dependent Hall data. Average Hall mob ilities 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 in dicate that the fitted bulk mobility is much higher for this sample, a pproximately 1.8 x 10(5) cm(2)/Vs. Samples grown on InAs substrates we re measured using high resolution Fourier transform photoluminescence spectroscopy and reveal new excitonic and impurity band emissions in I nAs including acceptor bound exciton ''two hole transitions.'' Two dis tinct shallow acceptor species of unknown chemical identity have been observed.