Accession Number : AD0623668

Title :   IMPURITY AND EXCITON EFFECTS ON THE INFRARED ABSORPTION EDGES OF III-V COMPOUNDS,

Corporate Author : PURDUE UNIV LAFAYETTE IND

Personal Author(s) : Johnson,E. J. ; Fan,H. Y.

Report Date : 08 APR 1965

Pagination or Media Count : 11

Abstract : The fundamental absorption edge of each of several III-V compounds was examined for structure due to excitons and impurities using high resolution and sample temperatures down to 1.4K. The effects of an applied magnetic field were studied. The absorption edge of GaSb shows three sharp peaks (a, b, c) and a lowabsorption tail. Under a magnetic field, the peaks (a, b, c) shift and split in a manner close to the expected behavior of the exciton. The peak a is shown to be the free-exciton peak and the peaks (b and c) are attributed to impurity-exciton complexes. The tail is found to be associated with electron transitions to the conduction band from impurity levels near the valence band. Absorption associated with impurityvalence-band transitions is also observed at low photon energies. Analysis of these results gives the energy gap, the electron g factor, and the ionization energies of impurity levels. The absorption edge of InSb shows a step which is found to be due to ionized acceptors. Under a magnetic field, two peaks develop from the step absorption which behave like the impurity-exciton peaks in GaSb. The optical transitions involved appear to be related to the emission observed in the InSb laser. The electron g factor and the ionization energies of impurity levels have been estimated from these results. Some studies on the impurity absorption near the intrinsic edge of other III-V compounds are reported. (Author)

Descriptors :   (*ABSORPTION SPECTRA, SEMICONDUCTORS), (*SEMICONDUCTORS, INFRARED SPECTRA), IMPURITIES, BAND SPECTRA, ELECTRON TRANSITIONS, MAGNETIC PROPERTIES, LASERS, CRYOGENICS, INTERMETALLIC COMPOUNDS, GALLIUM ALLOYS, ANTIMONY ALLOYS, INDIUM ALLOYS

Distribution Statement : APPROVED FOR PUBLIC RELEASE