Preparation and properties of evaporated CdTe films compared with single-crystal CdTe. Progress report No. 5, November 1, 1981-January 31, 1982
The hot-wall vacuum evaporator system has been put into use with successful deposition of seven thin films of n-type CdTe on glass. Microprobe analysis indicated that the films were stoichiometric CdTe. Optical transmission showed a well-defined absorption edge. Film resistivities on glass were reduced from 1.7 x 10/sup 8/ ohm-cm, to 6 x 10/sup 4/ ohm-cm by In doping; film resistivities under AM1.5 illumination are 2.0 x 10/sup 4/ and 5 x 10/sup 2/ ohm-cm, respectively compared to the dark values given above. Temperature dependence of the dark conductivity of the undoped CdTe film indicates an activation energy of 0.79 eV; in the light the activation energy was reduced to 0.1 eV. The high dark resistivity and activation energy indicate high intergrain potential barriers, which could produce the high resistivities observed even with fairly high free electron densities in the grains. Comparison will be sought between these results and those found for films deposited epitaxially on single crystal substrates. A detailed summary of absorption constant vs wavelength data for CdTe has been assembled for both single crystal and thin film materials. The absorption constant for thin film material appears to vary from 2 x 10/sup 4/ cm/sup -1/ at 8000A to 10/sup 5/ cm/sup -1/ at 5000A; single crystal values may be slightly higher. EBIC and light scanning techniques are being developed for characterizing grain boundary effects in bicrystals, and to evaluate the effects of passivation techniques. Defect densities at a grain boundary in a p-type bicrystal were found to range from 2 x 10/sup 12/ to 8 x 10/sup 12/ cm/sup -2/eV/sup -1/, using data derived from the J-V dependence of the grain boundary.
- Research Organization:
- Stanford Univ., CA (USA). Dept. of Materials Science and Engineering
- DOE Contract Number:
- AC02-77CH00178
- OSTI ID:
- 6814139
- Report Number(s):
- SERI/PR-9330-1-T5; ON: DE82011043
- Country of Publication:
- United States
- Language:
- English
Similar Records
Grain boundary phenomena in n-type CdTe films grown by hot wall vacuum evaporation
Investigating Local Carrier Dynamics in PERC Patterned CdTe Solar Cells
Related Subjects
CADMIUM TELLURIDES
ELECTRICAL PROPERTIES
OPTICAL PROPERTIES
VACUUM EVAPORATION
ABSORPTIVITY
ACTIVATION ENERGY
CRYSTAL DOPING
ELECTRIC CONDUCTIVITY
EXPERIMENTAL DATA
FILMS
GLASS
GRAIN BOUNDARIES
INDIUM ADDITIONS
LIGHT TRANSMISSION
N-TYPE CONDUCTORS
PASSIVATION
SPECTRAL RESPONSE
STOICHIOMETRY
ALLOYS
CADMIUM COMPOUNDS
CHALCOGENIDES
CRYSTAL STRUCTURE
DATA
ENERGY
EVAPORATION
INDIUM ALLOYS
INFORMATION
MATERIALS
MICROSTRUCTURE
NUMERICAL DATA
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
SEMICONDUCTOR MATERIALS
TELLURIDES
TELLURIUM COMPOUNDS
CDTE FILMS SINGLE-CRYSTAL
EVAPORATED
HOT-WALL VACUUM EVAPORATOR
SOLAR
140501* - Solar Energy Conversion- Photovoltaic Conversion