Formation energies and energy levels of deep defects in narrow gap semiconductors
- Florida Inst. of Tech., Melbourne, FL (United States). Physics and Space Sciences Dept.
The authors use a Green`s function technique for deep defect energy level calculations in mercury cadmium telluride (MCT), mercury zinc telluride (MZT), and mercury zinc selenide (MZS). The formation energy is calculated from the difference between the total binding energy with an impurity cluster and with a perfect cluster. These alloys are among those that have been experimentally grown in microgravity aboard the Space Shuttle. To evaluate the quality of these crystals, it is necessary to characterize them, and one important aspect of this characterization is the study of deep defects which can limit carrier lifetime. Relaxation effects are calculated with molecular dynamics. The resulting energy shift can be greater for the interstitial case than the substitutional one. Relaxation in vacancies is also considered. The charged state energy shift (as computed by a modified Haldane-Anderson model) can be twice that caused by relaxation. However, different charged states for vacancies had little effect on the formation energy. For all cases the authors considered the concentration of Cd or Zn in the range appropriate for a band gap of 0.1 eV. The emphasis of their calculation is on chemical trends. Only limited comparison to experiment and other calculations is possible, but what there is supports the statement that their results are at least of the right order of magnitude.
- Sponsoring Organization:
- National Aeronautics and Space Administration, Washington, DC (United States)
- OSTI ID:
- 500872
- Report Number(s):
- CONF-960848-; ISBN 0-8194-2197-9; TRN: IM9732%%100
- Resource Relation:
- Conference: Denver `96: 1. conference on space processing of materials, at SPIE International Society for Optical Engineering (SPIE) annual international symposium on optical science, engineering, and instrumentation, Denver, CO (United States), 4-9 Aug 1996; Other Information: PBD: 1996; Related Information: Is Part Of Space processing of materials; Ramachandran, N. [ed.] [Universities Space Research Association, Huntsville, AL (United States)]; PB: 411 p.; Proceedings/SPIE, Volume 2809
- Country of Publication:
- United States
- Language:
- English
Similar Records
Energetics of intrinsic defects and their complexes in ZnO investigated by density functional calculations
Ab initio based calculations of vacancy formation and clustering energies including lattice relaxation in Fe{sub 3}Al