HOT-CARRIER PHOTOLUMINESCENCE FROM GAAS V-GROOVE QUANTUM WIRES

We report measurements of hot-carrier photoluminescence from GaAs V-groove quantum wires. cw spectra reveal distinct one-dimensional subbands: at low excitation density recombination from laterally confined n(y) = 1 states is dominant, which shows that carriers relax efficiently to the lowest subband; n(y) = 2 and 3 recombination becomes pronounced at higher temperature and density, which indicates inhibited relaxation, possibly due to band filling. Time-resolved photoluminescence measurements at 10 K show a rise time of approximately 100 ps, which is due to energy relaxation. At later times the intensity of the n(y) = 1 line shows a monotonic decay at low carrier density, but there is a pronounced plateau at high density that extends for approximately 200 ps. These results provide clear evidence of carrier relaxation and band filling in quantum wires.