Scanning tunneling microscopic analysis of Cu(In,Ga)Se{sub 2} epitaxial layers

Journal Article · Mon Feb 15 00:00:00 EST 2010 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3304919· OSTI ID:21476136

Mayer, Marie A; Hebert, Damon; Rockett, Angus A ^[1]; Ruppalt, Laura B; Lyding, Joseph ^[2]

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1. Department of Materials Science and Engineering, University of Illinois, 1304 W. Green Street, Urbana, Illinois 61801 (United States)
2. Department of Electrical and Computer Engineering and Beckman Institute, University of Illinois, 3065 Beckman Institute, 405 N. Matthews St., Urbana, Illinois 61801 (United States)

Scanning tunneling microscopy (STM) measurements have been made on single-crystal epitaxial layers of CuInSe{sub 2} grown on GaAs substrates. Results were obtained for as-grown, air-exposed, and cleaned surfaces; in situ cleaved surfaces; surfaces sputtered and annealed in the STM system; and samples prepared by a light chemical etch. Conventional constant-current topographs, current-voltage curves, and current imaging tunneling spectroscopy (CITS) scans were obtained. Topographic images show that the surfaces appear rough on the atomic scale and often exhibit regular features consistent with a previously proposed surface ad-dimer reconstruction. CITS scans show a spatially varying energy gap consistent with band-edge fluctuations on a scale of a few atomic spacings. Energy variations were observed in both band edges. Although quantitative description of the magnitude of these fluctuations is difficult, the fluctuations on the atomic scale appear much larger than observed by methods such as photoluminescence, which average over larger volumes.

• OSTI ID: 21476136
• Journal Information: Journal of Applied Physics, Vol. 107, Issue 3; Other Information: DOI: 10.1063/1.3304919; (c) 2010 American Institute of Physics; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANNEALING
CHEMICAL VAPOR DEPOSITION
COPPER COMPOUNDS
ELECTRIC CONDUCTIVITY
ENERGY GAP
EPITAXY
FLUCTUATIONS
GALLIUM ARSENIDES
INDIUM COMPOUNDS
INDIUM SELENIDES
LAYERS
MONOCRYSTALS
PHOTOLUMINESCENCE
SCANNING TUNNELING MICROSCOPY
SEMICONDUCTOR MATERIALS
SPUTTERING
SUBSTRATES
SURFACE CLEANING
SURFACES
ARSENIC COMPOUNDS
ARSENIDES
CHALCOGENIDES
CHEMICAL COATING
CLEANING
CRYSTAL GROWTH METHODS
CRYSTALS
DEPOSITION
ELECTRICAL PROPERTIES
EMISSION
GALLIUM COMPOUNDS
HEAT TREATMENTS
LUMINESCENCE
MATERIALS
MICROSCOPY
PHOTON EMISSION
PHYSICAL PROPERTIES
PNICTIDES
SELENIDES
SELENIUM COMPOUNDS
SURFACE COATING
SURFACE FINISHING
TRANSITION ELEMENT COMPOUNDS
VARIATIONS