lntersubband Relaxation in Step Quantum Well Structures

lntersubband transitions in pseudomorphic lnGaAs/GaAs/ AIGaAs multiple step quantum wells

Intersubband transitions from the ground state to the first and second excited states in pseudomorphic AlGaAs/lnGaAs/GaAs/ AlGaAs multiple step quantum wells have been observed. The step well structure has a configuration of two A1GaAs barriers confining an InGaAs/GaAs step. Multiple step wells were grown on GaAs substrate with each InGaAs layer compressively strained. During the growth, a unif...

Intersubband relaxation dynamics in semiconductor quantum structures

We monitor the temporal evolution of the electron population in the first and second subband of an undoped GaAs/AlGaAs asymmetric double quantum well after interband optical excitation by using an interband pump/intersubband probe technique. The spacing between the two subbands is smaller than the longitudinal optical phonon energy. We extract an intersubband lifetime of T21 = 100 ps and a reco...

Continuous voltage tunability of intersubband relaxation times in coupled SiGe quantum well structures using ultrafast spectroscopy.

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 th...

Interwell relaxation times in p-Si/SiGe asymmetric quantum well structures: Role of interface roughness

Marco Califano,1 N. Q. Vinh,2 P. J. Phillips,3 Z. Ikonić,1 R. W. Kelsall,1 P. Harrison,1 C. R. Pidgeon,3 B. N. Murdin,4 D. J. Paul,5 P. Townsend,5 J. Zhang,6 I. M. Ross,7 and A. G. Cullis7 1Institute of Microwaves and Photonics, School of Electronic and Electrical Engineering, University of Leeds, Leeds, LS2 9JT, United Kingdom 2FOM Institute for Plasma Physics “Rijnhuizen,” P. O. Box 1207, NL-...

Carrier-carrier relaxation kinetics in quantum well semiconductor structures with nonparabolic energy bands