Photo-excited states in germanium at liquid helium temperatures

Thesis/Dissertation · Sat Jan 01 04:00:00 EST 1983

OSTI ID:6224101

Culbertson, J C

The first absolute measurement of the density dependence of the enhancement factor g/sub eh/(O) for the EHL in Ge is reported. This factor is a measure of the electron-hole spatial correlation function, and provides a valuable and sensitive test for the predictions of various many-body-theory approximations. A EHL droplet - FE gas system confined to a strain induced potential well was used. The measurement approach relies on only a few simple and verifiable assumptions. The results presented here agree quantitatively with the predictions of two different many-body-theory approximations. A byproduct of this work was the measurement as a function of stress of: the electron and hole Fermi levels, the EHL density, the condensation energy of a FE relative to the EHL, and the binding energy of a FE relative to free carriers (FC). The EHL decay was also characterized. The first direct measurement of the FE diffusivity D/sub x/ is reported. The evolution in time of spatial profiles of FE luminescence were measured. From these FE density profiles, D/sub x/(4.2K) = 300/sup 2/cm s/sup -1/, the surface recombination velocity S = 3000 cm s/sup -1/, and the FE lifetime tau/sub x/ = 27 ..mu..s with surface effects excluded were determined. It is observed that surface recombination may have dramatically effected previous measurements of tau/sub x/. An electron-phonon scattering time tau/sub p/ = 2 x 10/sup -10/s is inferred.

• Research Organization: California Univ., Berkeley (USA)
• OSTI ID: 6224101
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
656000 -- Condensed Matter Physics
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
DIFFUSION LENGTH
DIMENSIONS
ELECTRONIC STRUCTURE
ELEMENTS
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EXCITATION
EXCITONS
FERMI LEVEL
GERMANIUM
LENGTH
MANY-BODY PROBLEM
METALS
QUASI PARTICLES
RECOMBINATION