LIQUID-PHASE EPITAXY AND PHOTOLUMINESCENCE CHARACTERIZATION OF P-TYPE GASB LAYERS GROWN FROM BI BASED MELTS

Liquid phase epitaxy (LPE) of GaSb from Bi based melts was studied in the growth temperature interval from 390-550 degrees C. The layers exhibit p-type conductivity with acceptor concentrations in the order of 10(16) cm(-3). Photoluminescence (PL) spectra of layers grown below 450 degrees C are dominated by the bound exciton line BE4 at 795.2 meV and exhibit well resolved BE1, BE2, and BE3 lines. The line due to the band-''native'' acceptor recombination (A-line) appears at 776.6 meV. The intensity ratio A/BE4 is 0.04, indicating a ''native'' acceptor (NA) concentration much lower than 10(17) cm(-3). A new PL line at 796.8 meV is ascribed to a band-shallow acceptor transition with an acceptor activation energy of 13.4 meV. A bandgap reduction of 0.8 meV is found in GaSb:Bi layers, indicating a concentration of similar to 0.015 at% of electrically inactive Bi.