Regensburg 1998 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 29: Transporteigenschaften
HL 29.7: Vortrag
Donnerstag, 26. März 1998, 12:00–12:15, H17
Photoconductivity of double-barrier resonant tunneling structure with 2D and 3D emitter sources — •S. Vitusevich1, A. Belyaev2, T. Figielski3, K. M. Indlekofer1, A. F"orster1, H. L"uth1, and R. Konakova2 — 1Institut f"ur Schicht- und Ionentechnik, Forschungszentrum J"ulich GmbH, D-52425 J"ulich — 2Institut of Semiconductor Physics, National Academy of Sciences of Ukraine,Kiev 252028, Ukraine — 3Institute of Physics, Polish Academy of Sciences, Warsaw 02-668, Poland
Resonant tunneling structures are an object of increasing attention due to the realization of multivalued characteristics at room temperature. In this work for the first time photoassisted tunneling was observed from two sources of resonant tunneling current formation. Double barrier AlAs(2nm)/GaAs(4nm) heterostructure was grown by MBE. Structures contain wide undoped spacer layer 100 nm adjacent to one side of heavy doped emitter. Spectra of photoconductivity were measured at liquid nitrogen by modulation technique at several fixed voltages. Results demonstrated that the additional photo current is strictly depended on the polarity and the value of the applied voltage. In photoinduced valley current only interband absorption due to the GaAs gap is observed, while at resonant transmission condition additional maxima appear. The observed peculiarities of photo induced current are explained by strong changes in redistribution of the electrical field at nonresonant and resonant condition.