Hydrogen Migration and Complex Formation in Technologically Important III-V andII-VI Semiconductors and Their Alloys

摘要

Experimental and theoretical studies were conducted to identify basic mechanismsand provide quantitative information on the properties of hydrogen in selected (technologically-important) III-V and II-VI semiconductors and their alloys. Hydrogen interactions with dopants and deep level defects were investigated in GaAs, AlGaAs, InGaAs/AlGaAs quantum wells, GaP, GaN, and ZnSe.The diffusivity of H+ in GaAs was determined with a new capacitance transient technique, which provided the first direct quantitative determination of the diffusivity of hydrogen in any compound semiconductor. Vibrational mode spectroscopy identified the N-H complex in ZnSe:N and the Zn-H complex in GaP:Zn. Hydrogenation of Mg-doped GaN produced acceptor passivation. New local vibrational modes were detected in MBE-grown, Mg-doped GaN. Computational studies were conducted on native defects in Ga N with the conclusion that, contrary to a wide-spread assumption, the nitrogen vacancy cannot be the source of the high n-type conductivity generally found in as-grown undoped GaN. Electronic defects were characterized in n-type GaN by deep level transient spectroscopy (DLTS) and optical-DLTS. Finally, in epitaxial ZnSe the effects of hydrogenation during gas-source (e.g., H2Se) MBE were found to be significantly enhanced when N was used as the acceptor dopant and resulted in highly resistive films, while Cl-doped n-type films were largely unaffected by the presence of hydrogen during growth. jg.