title: Continuous voltage tunability of intersubband relaxation times in coupled SiGe quantum well structures using ultrafast spectroscopy.
abstract: We demonstrate continuous voltage control of the nonradiative transition lifetime in semiconductor heterostructures. The results were obtained by picosecond time-resolved experiments on biased SiGe valence band quantum well structures using a free electron laser. By varying the applied voltage, the intersubband hole relaxation times for quantum well structures were varied by a factor of 2 as the wave functions and their overlaps were tuned. The range of magnitudes for the lifetime indicates a possible route to silicon-based quantum cascade lasers.
authors.affiliation: Institute of Semiconductor and Solid State Physics, University of Linz, Linz, Austria.
authors.forename: P
authors.initials: P
authors.lastname: Rauter
authors.forename: T
authors.initials: T
authors.lastname: Fromherz
authors.forename: N Q
authors.initials: NQ
authors.lastname: Vinh
authors.forename: B N
authors.initials: BN
authors.lastname: Murdin
authors.forename: G
authors.initials: G
authors.lastname: Mussler
authors.forename: D
authors.initials: D
authors.lastname: Grützmacher
authors.forename: G
authors.initials: G
authors.lastname: Bauer