STUDY OF SURFACE STOICHIOMETRY AND LUMINESCENCE EFFICIENCY OF NEAR-SURFACE QUANTUM-WELLS TREATED BY HYDROGEN-IONS AND ATOMIC-HYDROGEN

A near-surface quantum well (QW) structure has been used as an effecti ve probe of surface states before and after different hydrogen treatme nts. By correlating the surface composition with the luminescence effi ciency of the near-surface QW, we find that the surface passivation is dominated by the defect density of the interface between the AlGaAs s urface barrier and the overlying oxide. A complete recovery or further enhancement of luminescence can be readily achieved by treatments usi ng hydrogen ions. However, atomic hydrogen at low exposures is not cap able of modifying that interface, and is not effective in passivation. These results corroborate a passivation mechanism which involves remo val of As from the interface between the AlGaAs surface barrier and th e overlying oxide, and the reduction of interface state density.