Cuprous oxide--indium--tin oxide thin film photovoltaic cells

Journal Article · Wed Jun 01 04:00:00 EDT 1983 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.332427· OSTI ID:6107492

Fujinaka, M; Berezin, A A

We studied thin films of cuprous oxide deposited on glass coated with transparent conducting indium--tin oxide (ITO) films. The deposition of both Cu/sub 2/O and ITO was made by rf sputtering in an Ar/O/sub 2/ gas mixture. For the deposition of Cu/sub 2/O a pure copper target was used and ITO films were deposited from a disk target, the halves of which were made of Sn and In, respectively. This allows variation of the stoichiometry of the deposited ITO film by changing the position of the substrate glass beneath the Sn/In target. X-ray diffraction of Cu/sub 2/O films indicates the typical pattern of amorphous material. We were able to produce Cu/sub 2/O films of different stoichiometry by varying the O/sub 2/ to Ar ratio during rf sputtering. The maximum resistivity of the films corresponds to an ideal stoichiometry of Cu/sub 2/O. An activation energy of 0.55 eV found from thermostimulated conductivity is related to excess Cu vacancies. The band gap found from the spectral dependence of the photovoltaic effect is 2.0 eV. The composition of ITO films was studied by Auger analysis and can be described as a variable composition mixture of SnO/sub 2+x/ and In/sub 2/O/sub 3+y/. To produce an Ohmic electrode, gold was evaporated on the top of the Cu/sub 2/O film and hence the resulting structure of the photocell could be specified as ITO--Cu/sub 2/O--Au, for which we propose a barrier band diagram. We studied the photovoltaic characteristics of the fabricated photocells under an incandescent lamp with approx. =100 mW/cm/sup 2/ output. The open-circuit voltage and short-circuit current of our cells were about 20--90 mV and 50 ..mu..A/cm/sup 2/, respectively, and some dependence of the output characteristics on the composition of ITO film was observed. Conversion efficiency for thin films Cu/sub 2/O/ITO cells was found to be substantially lower than for Cu/sub 2/O/Cu Schottky barrier cells. This is tentatively attributed to small diffusion lengths and/or presence of interface recombination centers.

• Research Organization: Department of Electronics, Tokyo Denki University, Chiyoda-Ku, Tokyo 101, Japan
• OSTI ID: 6107492
• Journal Information: J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 54:6; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140501* -- Solar Energy Conversion-- Photovoltaic Conversion
ACTIVATION ENERGY
AMORPHOUS STATE
ARGON
CHALCOGENIDES
COHERENT SCATTERING
COPPER
COPPER COMPOUNDS
COPPER OXIDE SOLAR CELLS
COPPER OXIDES
DATA
DEPOSITION
DIFFRACTION
DIMENSIONS
DIRECT ENERGY CONVERTERS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTS
ENERGY
ENERGY GAP
EQUIPMENT
EXPERIMENTAL DATA
FABRICATION
FILMS
FLUIDS
GASES
INDIUM COMPOUNDS
INDIUM OXIDES
INFORMATION
METALS
NONMETALS
NUMERICAL DATA
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
PHYSICAL PROPERTIES
RARE GASES
RF SYSTEMS
SCATTERING
SOLAR CELLS
SOLAR EQUIPMENT
SPUTTERING
STOICHIOMETRY
THICKNESS
TIN COMPOUNDS
TIN OXIDES
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
X-RAY DIFFRACTION