Theory of Te precipitation and related effects in CdTe crystals
- Solid State Physics Lab., Delhi (India)
A thermodynamic calculation is presented which explains the origin of often reported large stress fields in and around Te precipitates and associated punching of dislocation loops in star like patterns. The calculation is based on the consideration that the stoichiometric deviation in Te saturated crystals are accommodated by Te interstitials, Cd multivacancy complexes and Te antisites; the Te interstitials are most mobile of them, and dominate the precipitation process; and the precipitates when they appear first are in droplet form. The droplet state is modelled on the basis of the Lennard-Jones 6-12 interaction potential. The droplet growth is envisaged to occur via the following two processes operating in tandem: first, capture of excess Te interstitials to cause droplet overpressurization, and then, punching of interstitial dislocation loops whenever the pressure exceeds a threshold value. The flow of Te interstitials into the droplets is driven by the difference between their formation energies in the lattice and the free energy change of the droplets per Te atom added. It is shown that the achievable droplet pressures far exceed that required for the loop punching and sustaining the growth cycle. The occurrence of varying precipitate morphologies are explained, and the possibility of nucleating high pressure Te phases is examined. Some experimental evidence is also presented which corroborate the theoretical arguments involved. 71 refs., 8 figs.
- OSTI ID:
- 5536533
- Journal Information:
- Journal of Electronic Materials (A.I.M.E. Metallurgical Society); (United States), Vol. 21:10; ISSN 0361-5235
- Country of Publication:
- United States
- Language:
- English
Similar Records
Two-Step Annealing to Remove Te Secondary-Phase Defects in CdZnTe While Preserving the High Electrical Resistivity
Effects of electron irradiation on precipitation in Al-3.5% Cu
Related Subjects
36 MATERIALS SCIENCE
CADMIUM TELLURIDES
THERMODYNAMIC PROPERTIES
MATHEMATICAL MODELS
FREE ENERGY
LENNARD-JONES POTENTIAL
PRECIPITATION
SOLAR CELLS
STRESSES
CADMIUM COMPOUNDS
CHALCOGENIDES
DIRECT ENERGY CONVERTERS
ENERGY
EQUIPMENT
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
PHYSICAL PROPERTIES
POTENTIALS
SEPARATION PROCESSES
SOLAR EQUIPMENT
TELLURIDES
TELLURIUM COMPOUNDS
140501* - Solar Energy Conversion- Photovoltaic Conversion
360601 - Other Materials- Preparation & Manufacture
360606 - Other Materials- Physical Properties- (1992-)