IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Applied Surface Analysis Monday Sessions
       Session AS-MoP

Paper AS-MoP4
Defect Layer Detection at the Surface of Polycrystalline Cu(In,Ga)Se@sub2@ by SIMS Depth Profiling, AES, SEM and TEM

Monday, October 29, 2001, 5:30 pm, Room 134/135

Session: Student Poster Competition/Aspects of Applied Surface Analysis I Poster Session
Presenter: S.E. Asher, NREL
Authors: S.E. Asher, NREL
F.S. Hasoon, NREL
H. Althani, NREL
K.M. Jones, NREL
C.L. Perkins, NREL
M.R. Young, NREL
Correspondent: Click to Email
Polycrystalline thin-film solar cells based on the ternary chalcopyrite semiconductor Cu(In,Ga)Se@sub@2 (CIGS) have produced devices with the highest recorded efficiencies for any thin film technology, near 19%.At NREL, absorber films are grown using a three-stage process with co-evaporation of the elements in a Se atmosphere.@footnote 1@ The growth parameters of the final stage are important to obtaining high efficiency devices. Recently, cross-sectional SEM and TEM results have shown that certain third-stage growth conditions result in the formation of a defect layer near the surface of the absorber layer. This layer can be up to 250 nm thick depending on conditions. However, despite the change in microstructure, Auger depth profiles across this interface do not reliably show the presence of a compositional change. We have found that a simple SIMS depth profile following Na correlates well with the existence of the defect layer near the surface of the CIGS layer. We believe this is due to increased Na incorporation along the defects and grain boundaries in this layer. In this study, SIMS results are correlated with AES compositional profiles and SEM and TEM micrographs. SIMS provides a rapid means to access compositional changes occuring in the near surface region of the CIGS absorbers. @FootnoteText@ @footnote 1@A.M. Gabor, J.R. Tuttle, D.S. Albin, M.A. Contreras, and R. Noufi, Appl. Phys. Lett., 65, 198, 1994.