Optical measurement of surface recombination in InGaAs quantum well mesa structures

Surface recombination of optically created electron-hole plasma in InGaAs/InP quantum well mesa structures formed by chemical beam epitaxy followed by anisotropic plasma etching is observed optically by a picosecond pump-probe method. The exponential carrier lifetime in 3.3-μm-diam structures is reduced from 31 ns as measured for large diameters to 5.5 ns. We ascribe this reduction to a surface recombination velocity of 1.2×104 cm/s. The surface recombination velocity is about two orders of magnitude smaller than those reported for bulk GaAs layers exposed to air.