Microstructures and electrical characterization of CVD-W and Mo films as contacts in photocells

Conference · Tue Aug 01 04:00:00 EDT 1995

OSTI ID:82559

Gesheva, K A; Stoyanov, G I; Stefanov, R ^[1]; Vlakhov, E S ^[2]

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1. Bulgarian Academy of Science, Sofia (Bulgaria). Central Lab. of Solar Energy and New Energy Sources
2. Bulgarian Academy of Sciences, Sofia (Bulgaria). Inst. of Solid State Physics

Tungsten and molybdenum hexacarbonyls were used as precursors in chemical vapor deposition process for preparation of W and Mo thin films. Pyrolitical decomposition of these precursors proceeds at temperatures of 250--400 C. Thin films with thicknesses in the range of 0,02--1 {mu}m monocrystalline Se. Microstructural studies performed by Reflection High Energy Electron Diffraction (RHEED) method showed that films deposited tend to grow textures. This is discussed as probably due to differences in the growth rate for various crystal planes. The sheet resistances of the as-deposited W and Mo films are in the range of 20--30 {Omega}/{open_square} for thicknesses of 0.15 {micro}m. After thermal annealing the resistance of W films drops to about 2 {Omega}{open_square} and for Mo films to about 9{Omega}{open_square}. Decreasing in the resistivity of the films is tightly connected with the decreasing in the impurities concentration. These impurities are considered to be in the base of the observed behavior of the temperature dependence of the electrical resistance of the films. The CVD-W and Mo films are studied as back contacts on CdTe layer in CdS/CdTe photocells. In the paper some preliminary results are presented for the sheet and contact resistances when CVD W and Mo films are deposited at lower temperatures on the surface of CdTe layers, deposited by close-spaced sublimation method. The thin film materials, produced by CVD technology look promising with respect to the required high deposition rates and extremely wide deposition areas in the mass production of solar cells.

• OSTI ID: 82559
• Report Number(s): CONF-941144--; ISBN 1-55899-264-2
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANNEALING
AUGER ELECTRON SPECTROSCOPY
CADMIUM
CARBONYLS
CHEMICAL REACTION KINETICS
CHEMICAL VAPOR DEPOSITION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTRON MICROPROBE ANALYSIS
GLASS
MICROSTRUCTURE
MOLYBDENUM
MORPHOLOGY
SCANNING ELECTRON MICROSCOPY
SILICON
TELLURIUM
TUNGSTEN