A249 520
Surface Science 170 (1986) 520-525 North-Holland, Amsterdam
HIGH FIELD DRIFT VELOCITIES OF TWO-DIMENSIONAL IN GaAs/AlGaAs QUANTUM WELL STRU...
HIGH FIELD DRIFT VELOCITIES OF TWO-DIMENSIONAL IN GaAs/AlGaAs QUANTUM WELL STRUCTURES R.A. HGPFEL and J. SHAH A T&T Bell Lahorurorm,
CARRIERS
Holmdel. New Jersey 07733, USA
and A.C. GOSSARD AT&T
and W. WIEGMANN
Bell Laboratories,
Received
Murru_v Hill. New Jersey 07974, USA
29 July 1985: accepted
for publication
13 September
1985
We report direct measurements of the high field drift velocities of photoexcited electrons in time-of-flight p-type multiple quantum well structures of GaAs/Al (, 4xGa,, sI As by picosecond techniques. Negative differential mobility is observed at electric fields > 8 kV/cm. caused by real-space and valley transfer of hot carriers into Al ,Ga, ~, As. which is an indirect semiconductor at .Y = 0.48. From the photoluminescence spectra the carrier temperatures, at which the transfer effects occur, are determined.
SCREENED ELECTRON-POLAR OPTIC PHONON INTERACTION AND POWER LOSS OF HOT ELECTRONS IN BULK GaAs AND IN QUANTUM WELLS P.K. BASU and Sudakshina KUNDU Cenrre of Admmced Study in Radio Phwrcs and Eleciromcs. Culcurra 700009, India Received
13 July 1985; accepted
The power loss of hot matrix element due to the experimental data for 2 K. in bulk for the same power
for publication
13 September
92 AchaTya PraJulla Chandra 1985
two-dimensional electrons in MQWs calculated by takmg the proper bulk nature of the phonons and the screening agrees well with the It is also found that the electron temperature is higher in MQWs than input.
THEORY OF ENERGY RELAXATION IN GaAs QUANTUM WELLS S. KATAYAMA General Education Department, Received
Road,
20 July 1985; accepted
531
OF 2D HOT CARRIERS
Niigata Uniuersity, Niigate 950.21, Japan for publication
13 September
1985
The energy relaxation rate of two-dimensional (2D) hot carriers due to LO phonon emission is explored theoretically by assuming a simple quantum-well structure for GaA-Al,Ga, _,As superlattices. The differences of energy loss rate between electrons and holes are shown with emphasis on the roles of free carrier screening and form factors. The picosecond cooling behavior of photoexcited 2D carriers is presented on the basis of the polar carrier-LO phonon coupling process.