COEXISTENCE OF THE DX CENTER AND OTHER SI-RELATED ELECTRON BOUND-STATES IN ALXGA1-XAS

The coexistence of the DX center with other donor-related bound states has been investigated in Si-doped direct gap AlxGai-xAs, by comparing electron denisty data obtained by capacitance/voltage and Hall measur ements. The experiments were carried out under saturated persistent ph otoconductivity conditions, as well as during isothermal capture trans ients. A D degrees bound state degenerated in energy with the conducti on band is populated through low temperature photo-ionization of the D X center. The D degrees level comes very close in energy to the Gamma minimum when the direct-to-indirect gap transition is approached. Unde r defined conditions, the final stage of isothermal capture transients is dominated by the electron freezing into hydrogenic bound states li nked to Gamma.