Structural and optical properties of (Ag,Cu)(In,Ga)Se{sub 2} polycrystalline thin film alloys

Journal Article · Sat Jun 14 00:00:00 EDT 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4880243· OSTI ID:22304188

Boyle, J. H.; Shafarman, W. N.; Birkmire, R. W. ^[1]; McCandless, B. E. ^[1]

---

1. Institute of Energy Conversion, University of Delaware, 451 Wyoming Road, Newark, Delaware 19716 (United States)

The structural and optical properties of pentenary alloy (Ag,Cu)(In,Ga)Se{sub 2} polycrystalline thin films were characterized over the entire compositional range at a fixed (Cu + Ag)/(In + Ga) ratio. Films deposited at 550 °C on bare and molybdenum coated soda-lime glass by elemental co-evaporation in a single-stage process with constant incident fluxes exhibit single phase chalcopyrite structure, corresponding to 122 spacegroup (I-42d) over the entire compositional space. Unit cell refinement of the diffraction patterns show that increasing Ag substitution for Cu, the refined a{sub o} lattice constant, (Ag,Cu)-Se bond length, and anion displacement increase in accordance with the theoretical model proposed by Jaffe, Wei, and Zunger. However, the refined c{sub o} lattice constant and (In,Ga)-Se bond length deviated from theoretical expectations for films with mid-range Ag and Ga compositions and are attributed to influences from crystallographic bond chain ordering or cation electronegativity. The optical band gap, derived from transmission and reflection measurements, widened with increasing Ag and Ga content, due to influences from anion displacement and cation electronegativity, as expected from theoretical considerations for pseudo-binary chalcopyrite compounds.

• OSTI ID: 22304188
• Journal Information: Journal of Applied Physics, Vol. 115, Issue 22; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BOND LENGTHS
CHALCOPYRITE
COPPER COMPOUNDS
CRYSTALLOGRAPHY
DIFFRACTION
ELECTRONEGATIVITY
EVAPORATION
GALLIUM COMPOUNDS
GLASS
INDIUM COMPOUNDS
LATTICE PARAMETERS
OPTICAL PROPERTIES
POLYCRYSTALS
REFLECTION
SELENIUM COMPOUNDS
SILVER COMPOUNDS
TERNARY ALLOY SYSTEMS
THIN FILMS