OPTICAL AND ELECTRICAL CHARACTERIZATION OF THICK GASB BUFFER LAYERS GROWN ON 2-IN GAAS WAFERS

We have investigated the growth of thick, highly uniform GaSb buffer l ayers on 2 in GaAs substrates. We have found that ramping the temperat ure under an arsine flux optimizes the switching sequence between GaAs and GaSb. In this case, the large (about 8%) lattice mismatch which s eparates the Ga-As and Ga-Sb bond lengths is abruptly relaxed, and goo d quality GaSb can be homogeneously deposited. On such samples, the ph otoluminescence signal ranks as well (or even better) as that obtained for comparative homoepitaxial material; also, the electrical properti es are among the best ever reported for GaSb grown by metal-organic ch emical vapor deposition on GaAs.