MOLECULAR-BEAM EPITAXIAL-GROWTH AND PROPERTIES OF SI-DOPED GAAS ALGAAS QUANTUM-WELLS/

We report on molecular beam epitaxial growth of Si doped, single and m ultiple quantum well structures. We have examined the effects of growt h parameters such as substrate temperature, group V/III ratio, and int entional and unintentional impurities, on the electrical and optical p roperties of the quantum wells structures. Capacitance-voltage and sec ondary ion mass spectrometry analysis of the structures reveal that th e net density of electrically active carriers in the wells is controll ed by the number of acceptor states in the AlGaAs barrier. We have ass igned the source of the acceptor state to the presence of oxygen in th e AlGaAs barrier. We observe that the strength of the intersubband opt ical absorption from the quantum wells increases linearly with the Si- doping in the well. Photoluminescence measurements indicate that for a given substrate temperature, a lower V/III ratio results in higher qu ality quantum well.