Study of growth temperature in gas-source molecular-beam epitaxy growth of InGaAs/GaAs quantum well lasers

Abstract

Strained-layer InGaAs/GaAs single quantum well lasers were grown by gas-source molecular-beam epitaxy at temperatures between 430 and 610 °C. The optimum growth temperature for the quantum wells of the lasers was found to be about 520 °C, as deduced from the measurement of threshold current density of the lasers and room-temperature photoluminescence (PL) of the quantum wells. If the growth temperature is lower than 520 °C, the threshold current density dramatically increases due to the formation of nonradiative carrier recombination centers in the quantum well. These recombination centers originate from lattice mismatch defects and alloy disordering. If the growth temperature is higher than 520 °C, indium desorption and segregation become increasingly severe. Thus, at high growth temperature, the InGaAs/GaAs interfaces become rough and the threshold current density increases. In addition, rapid thermal annealing was observed to remove most of the nonradiative recombination centers from the quantum wells and to improve the threshold current density of the lasers and PL intensity of the quantum wells.