Photoelectrochemical generation of hydrogen at electrochemically deposited p-CdTe films: Effect of heat-treatment, surface modification by platinum and surface oxide layer on conversion efficiency
The effects of heat-treatment, Pt modification of the surface and surface oxide layer on the efficiency for the photoelectrochemical generation of hydrogen were investigated at p-CdTe films deposited electrochemically at -0.35V (vs. Ag/AgC1) from an aqueous sulfuric acid solution of pH = 1.4 containing 1M CdSO/sub 4/ and 1 mM TeO/sub 2/. By heat-treatment in a He atmosphere, the crystalline diameter increased and, thus, the number of grain boundaries at which effective electron-hole recombination takes place decreased. Free metallic Te existing near the surface, which acts as a recombination center, was removed by the treatment at the temperatures above 350/sup 0/C. The cathodic photocurrent was increased by the heat-treatment due to these two effects. The cathodic photocurrent was decreased and even the anodic photocurrent was observed at the films treated at too high a temperature and for too long a time. The films were converted to n-type by these treatments because of the removal of the lattice Te from CdTe crystal. Pt modification, either vacuum deposition or codeposition, improved the efficiency, but the photocurrent is small, suggesting that the major reason for the low efficiency is still the bulk recombination. The oxide layer was easily formed on the CdTe films by exposure to air but dissolved by contacting with solution and had no effect on the photoelectrochemical properties of the film.
- Research Organization:
- Dept. of Chemistry, Faculty of Science, Hokkaido Univ., Sapporo 060
- OSTI ID:
- 6057370
- Journal Information:
- J. Electrochem. Soc.; (United States), Vol. 133:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
14 SOLAR ENERGY
HYDROGEN PRODUCTION
PHOTOELECTROLYSIS
CADMIUM SULFATES
CADMIUM TELLURIDES
ELECTRODEPOSITION
ENERGY EFFICIENCY
FILMS
HEAT TREATMENTS
HIGH TEMPERATURE
N-TYPE CONDUCTORS
P-TYPE CONDUCTORS
PH VALUE
PHOTOCURRENTS
PLATINUM
RECOMBINATION
SULFURIC ACID
SURFACE TREATMENTS
TELLURIUM OXIDES
CADMIUM COMPOUNDS
CHALCOGENIDES
CURRENTS
DEPOSITION
EFFICIENCY
ELECTRIC CURRENTS
ELECTROLYSIS
ELEMENTS
HYDROGEN COMPOUNDS
INORGANIC ACIDS
LYSIS
MATERIALS
METALS
OXIDES
OXYGEN COMPOUNDS
PLATINUM METALS
SEMICONDUCTOR MATERIALS
SULFATES
SULFUR COMPOUNDS
SURFACE COATING
TELLURIDES
TELLURIUM COMPOUNDS
TRANSITION ELEMENTS
080106* - Hydrogen- Production- Biosynthesis & Photochemical Processes
140505 - Solar Energy Conversion- Photochemical
Photobiological
& Thermochemical Conversion- (1980-)