THRESHOLD-LIKE BEHAVIOR OF PHOTOLUMINESCENCE IN LASER HETEROSTRUCTUREWAFERS

Thresholdlike behavior of photoluminescence (PL) in heterostructure wa fers is studied. It is shown that strictly speaking there is no pi, th reshold, and the thresholdlike dependence of PL on the pump power resu lts from the combination of three factors: the PL spreading along the wafer surface, the change in the radiative fraction of electron-hole r ecombination, and the restricted aperture of the PL detector. The firs t two factors were found to be dominating in the wafers studied. (C) 1 997 American Institute of Physics.