Increased Optoelectronic Quality and Uniformity of Hydrogenated p-InP Thin Films
Sutter-Fella, Carolin M.
Miller, D. Westley
Warren, Charles W.
Roe, Ellis T
Lonergan, Mark C
Guthrey, Harvey L.
Haegel, Nancy M.
Ager, Joel W.
KAUST DepartmentComputer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division
Electrical Engineering Program
KAUST Solar Center (KSC)
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AbstractThe thin-film vapor-liquid-solid (TF-VLS) growth technique presents a promising route for high quality, scalable and cost-effective InP thin films for optoelectronic devices. Towards this goal, careful optimization of material properties and device performance is of utmost interest. Here, we show that exposure of polycrystalline Zn-doped TF-VLS InP to a hydrogen plasma (in the following referred to as hydrogenation) results in improved optoelectronic quality as well as lateral optoelectronic uniformity. A combination of low temperature photoluminescence and transient photocurrent spectroscopy were used to analyze the energy position and relative density of defect states before and after hydrogenation. Notably, hydrogenation reduces the intra-gap defect density by one order of magnitude. As a metric to monitor lateral optoelectronic uniformity of polycrystalline TF-VLS InP, photoluminescence and electron beam induced current mapping reveal homogenization of the grain versus grain boundary upon hydrogenation. At the device level, we measured more than 260 TF-VLS InP solar cells before and after hydrogenation to verify the improved optoelectronic properties. Hydrogenation increased the average open-circuit voltage (VOC) of individual TF-VLS InP solar cells by up to 130 mV, and reduced the variance in VOC for the analyzed devices.
CitationIncreased Optoelectronic Quality and Uniformity of Hydrogenated p-InP Thin Films 2016 Chemistry of Materials
SponsorsMaterials characterization and growth was supported by the Electronic Materials Program funded by the Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. Device fabrication was supported by the Department of Energy through the Bay Area Photovoltaic Consortium under Award Number DE-EE0004946. J.-H. H. acknowledges KAUST and National Science Council of Taiwan (NSC 102-2911-I-002-552). C.M. S.-F. acknowledges financial support from the Swiss National Science Foundation (P2EZP2_155586).
PublisherAmerican Chemical Society (ACS)
JournalChemistry of Materials