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A study of interface problems in polycrystalline GaAs Schotky barrier and MIS solar cells
Author(s) -
Kazmerski L. L.,
Ireland P. J.
Publication year - 1979
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.740010503
Subject(s) - schottky barrier , x ray photoelectron spectroscopy , materials science , grain boundary , crystallite , schottky diode , diffusion barrier , diffusion , oxide , semiconductor , layer (electronics) , optoelectronics , analytical chemistry (journal) , chemistry , nanotechnology , chemical engineering , composite material , microstructure , metallurgy , physics , engineering , thermodynamics , diode , chromatography
AES, SIMS and XPS are used to investigate the interfaces in polycrystalline GaAs Schottky barrier and MIS solar cells. A significant interfacial chemical reaction is found to occur between Au and the GaAs in room temperature fabricated devices, with at least one phase, Ga 2 Au, identified using chemical peak shifts in XPS. Enhanced interdiffusion is reported at elevated temperatures for these structures. The primary mechanism is identified to be grain boundary diffusion, and the temperature dependence of the diffusion coefficient is estimated from the AES depth‐compositional data. The interface in the Ag/GaAs Schottky barrier is studied for comparison and is found to be stable to 573 K. The measured Schottky barrier heights and photovoltaic performances of these solar cells are correlated with the condition of the metal‐semiconductor interface. The advantage of including a thin oxide layer between the Au and GaAs (MIS structure) in preserving the integrity of the interfaces is demonstrated.