Polarized photomodulated reflectivity and photoluminescence studies of ordered InGaP{sub 2} under pressure
- Missouri Univ., Columbia, MO (United States)
- Sandia National Labs., Albuquerque, NM (United States)
Spontaneous ordering of ternary alloys grown on misoriented substrates has been of recent interest. Ordering induced band gap reduction, and valence band splittings exhibiting novel polarization properties have been investigated by theory and experiment. This paper discusses polarized photomodulated reflectivity (PR) and photoluminescence (PL) studies of MOCVD grown InGaP{sub 2} epilayers lattice-matched to a GaAs substrate. These structures were grown on a (001) face with a niisorientation of two degrees along <110>. The high degree of ordering has enabled us to accurately measure the crystal field splitting and additional structure not reported in the PR spectra. For the electric field E parallel to [110] two features in the PR spectra are seen; for E {parallel}[110], however, additional features are observed. Comparison with spectra of disordered samples of the same alloy composition has enabled a determination of the band gap reduction due to ordering. Linewidths of the PR peaks are approximately 5--10 meV which has enabled us to study them in detail as a function of hydrostatic pressure at cryogenic temperatures. The pressure dependence is slightly sublinear with the first order term of 8--9 meV/kbar for pressures well below the l-X crossover. Also observed is the indirect level crossing which occurs under pressure at about 40-kbar. A comparison of PR lineshapes at 1-bar is also presented at several commonly used experimental temperatures. Data indicate a substantial change in PR lineshapes, showing that interpretation of reflectivity data for these samples must be handled carefully.
- Research Organization:
- Sandia National Labs., Albuquerque, NM (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States); Department of Defense, Washington, DC (United States)
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 10171381
- Report Number(s):
- SAND-94-1002C; CONF-940846-1; ON: DE94016556; BR: GB0103012; CNN: DAAL-03-91-G-0381; TRN: 94:015502
- Resource Relation:
- Conference: 6. international conference on high pressures in semiconductor physics,Vancouver (Canada),22-24 Aug 1994; Other Information: PBD: [1994]
- Country of Publication:
- United States
- Language:
- English
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