OPTICAL CHARACTERIZATION OF GASB-BASED TERNARY AND QUATERNARY ALLOYS GROWN BY LIQUID-PHASE EPITAXY AT LOW-TEMPERATURES

GaSb and GaSb-based alloys are grown by liquid-phase epitaxy (LPE) and characterized by photoluminescence (PL) and Raman spectroscopies. Alt hough the concentration of the dominant native defect decreases with d ecreasing growth temperature, the crystalline quality of GaSb grown at 270-degrees-C is very poor: near-band-edge emission is not observed i n the PL measurement and a peak due to forbidden scattering strongly a ppears in the Raman spectrum. On the other hand, AlxGa1-xSb and Ga1-xI nxSb ternary alloys and AlxGa1-x-yInySb quaternary alloys grown at the same temperature exhibit much better crystal quality than the binary: the near-band-edge emission is clearly observed in the PL spectra and only the allowed mode is detected in the Raman measurement. Thus we c an improve the quality of the low-temperature-LPE-grown layer through alloying.