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Effects of Si incorporation and electrical activation of intersubband optical absorption in MBE-grown GaAs/AlGaAs multiple quantum well structures

Einbau und Aktivierung der Si-Dotierung und deren Einfluss auf die Intersubbandabsorption in GaAs/AlGaAs MQW-Strukturen

Wolford, D.J. ; Materials Research Society -MRS-:
Impurities, defects and diffusion in semiconductors. Bulk and layered structures. Symposium : Symposium held November 27 - December 1, 1989, Boston, Massachusetts, U.S.A.
Pittsburgh, Pa.: MRS, 1990 (Materials Research Society symposia proceedings 163)
ISBN: 1-558-99051-8
Symposium Impurities, Defects and Diffusion in Semiconductors <1989, Boston/Mass.>
Fraunhofer IAF ()
electronic Raman scattering; elektronische Ramanstreuung; FIR photodetectors; FIR Photodetektoren; GaAs; intersubband absorption; Intersubbandabsorption; MBE; Plasmon-Anregung; Plasmon excitation; SIMS

Using SIMS profiling temperature-dependent Hall measurements, electronic Raman scattering, and infra-red absorption, a detailed study is presented examining the effects of Si dopant behaviour on intersubband absorption in GaAs/Al sub .32 Ga sub .68 As MQW's. The samples were grown by molecular beam epitaxy at substrate temperatures ranging from 520 to 680 degree C with Si doping in the GaAs quantum wells only. SIMS profiling reveals that, with increasing substrate temperature, substantial Si migration into the Al sub.32 Ga sub .68 As barrier layers occurs during epitaxial growth. Hall measurements indicate that both at elevated growth temperatures and under reduced incident As sub 4 beam fluxes, the electron sheet concentration is reduced in the QW's. In both cases, loss of free carriers is attributed to enhanced Si compensation. Shifts in the absolute frequency of the infra-red absorption resonance, determined by electronic Raman scattering, as well as variations in the integrated abs orption intensity, are both shown to directly reflect the growth-induced variations in the free-carrier concentration in the quantum wells.