Accession Number:

ADA238149

Title:

Spatial Light Modulators with Arbitrary Quantum Well Profiles

Descriptive Note:

Annual technical rept. 14 Jan 90-14 Jan 91,

Corporate Author:

ARIZONA STATE UNIV TEMPE DEPT OF ELECTRICAL AND COMPUTER ENGINEERING

Report Date:

1991-01-14

Pagination or Media Count:

21.0

Abstract:

The program has successfully grown GaAsAGaAs triangular and parabolic compositionally graded wells by solid source SS Molecular Beam Epitaxy MBE and gas source GS molecular beam epitaxy GSMBE. In addition, strained in GaAsGaAs wells have also been grown. An optimization of growth conditions for obtaining narrow exciton linewidths in square and nonrectangular wells was completed. We have refined the superlattice compositional grading technique to obtain 3 meV photoluminescence linewidths in a triangular quantum well. A study of the optical properties has begun in which the structures are characterized by room temperature and 2K photoluminescence and photocurrent spectroscopies. Responsivity curves for structures having various well shapes have shown the excited states and a comparison with theory is in progress. A preliminary comparison of contrast ratios in rectangular and triangular SEED devices has been completed. Calculations of exciton transition energies, oscillator strength and modulator absorption ratios have successfully been performed for quantum wells having different profiles. The behavior of these structures as a function of electric field has also been performed. It was shown theoretically that asymmetric triangular quantum wells exhibit large contrast ratios at low electric fields.

Subject Categories:

  • Quantum Theory and Relativity
  • Solid State Physics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE