EVALUATION OF H-PLASMA AND THERMAL OXIDE DESORPTION PROCEDURES FOR MBE REGROWTH OF AN INP INGAAS/INP QUANTUM-WELL/

An InGaAs single quantum well structure has been used to investigate t he effect of H-plasma exposure for oxide removal and subsequent regrow th on InP surfaces. In addition, the H-plasma desorption is compared w ith the usual technique of thermal desorption of the oxide. Assessment of the optical quality of the regrowth interface has been achieved,by photoluminescence (PL), photoluminescence excitation (PLE) and photor eflectance (PR) spectroscopy studies of the quantum well grown directl y on the regrowth interface. It is shown that the effect of the H-plas ma itself on the InP surface can be minimized by applying a positive b ias of +30 V to the substrate or by annealing the substrate, For both the H-plasma and the thermal surface cleaning treatments, the regrowth procedure on air/UV-ozone exposed samples introduces non-radiative de fects which Strongly degrade the room-temperature PC efficiency. The r egrowth procedure also induces a defect-related peak in the low-temper ature PL spectra, 15 meV below the quantum well intrinsic PL line. The defect concentration is higher in the case of the H-plasma desorption than in thermal desorption, as deduced from PL measurements. The PLE and PR measurements confirm that the interface disorder is also higher in the H-plasma cleaned sample.