Accession Number : ADA193300


Title :   Ultrafast Physics in Semiconductor Microstructures.


Descriptive Note : Annual progress rept. 1 Dec 86-30 Nov 87,


Corporate Author : CITY COLL NEW YORK INST FOR ULTRAFAST SPECTROSCOPY AND LASERS


Personal Author(s) : Alfano, Robert


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a193300.pdf


Report Date : 19 Feb 1988


Pagination or Media Count : 108


Abstract : Analyzed is picosecond photoluminescence data obtained from quasi-two- and quasi-zero-dimensional electron systems in GaAs/AlGaAs multiple quantum wells and CdSSe/glass spherical quantum wells. Important results are: (i) nonequilibrium phonons produced in the energy relaxation process of quasi-two-dimensional carriers in a vicinity of phonon wave number q sub e could behave like coherent Bosons within a short time period. The effects of nonequilibrium phonons for photogenerated carriers in undoped GaAs quantum wells are to slow the energy relaxation and to shorten the recombination lifetime. (ii) Electron-hole recombination dynamics in quasi-OD was interpreted based on the carrier confinement model. Ultrafast expansion of carriers in asymmetric GaAs quantum wells as observed under picosecond excitation. Dynamical changes in the band structure of GaAs and GaSe were measured under shock waves. Effects of nonequilibrium phonons on the energy relaxation and recombination lifetime of photogenerated carriers in undoped GaAs quantum wells; Observation of ultrafast lateral expansion of energetic carriers in an asymmetric GaAs quantum well; Electron-hole recombination lifetimes in a quasi-two-dimensional electron system in CdS(x)Se(1-x).


Descriptors :   *PHOTOLUMINESCENCE , *QUANTUM THEORY , *SEMICONDUCTORS , BOSONS , GALLIUM ARSENIDES , HIGH RATE , HOLES(ELECTRON DEFICIENCIES) , MICROSTRUCTURE , PHONONS , PHYSICS , QUANTUM ELECTRONICS , RECOMBINATION REACTIONS , RELAXATION , SHOCK WAVES , ALUMINUM GALLIUM ARSENIDES , CADMIUM SELENIDES , SULFUR COMPOUNDS , GLASS


Subject Categories : Electrical and Electronic Equipment
      Solid State Physics


Distribution Statement : APPROVED FOR PUBLIC RELEASE