Transient terahertz photoconductivity measurements of minority-carrier lifetime in tin sulfide thin films: Advanced metrology for an early stage photovoltaic material
Author(s)Sher, Meng-Ju; Yang, Chuanxi; Hartman, Katy; Lindenberg, Aaron M.; Gordon, Roy G.; Jaramillo, Rafael; Ofori-Okai, Benjamin Kwasi; Steinmann, Vera; Nelson, Keith Adam; Buonassisi, Tonio; ... Show more Show less
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Materials research with a focus on enhancing the minority-carrier lifetime of the light-absorbing semiconductor is key to advancing solar energy technology for both early stage and mature material platforms alike. Tin sulfide (SnS) is an absorber material with several clear advantages for manufacturing and deployment, but the record power conversion efficiency remains below 5%. We report measurements of bulk and interface minority-carrier recombination rates in SnSthin films using optical-pump, terahertz-probe transient photoconductivity (TPC) measurements. Post-growth thermal annealing in H[subscript 2]S gas increases the minority-carrier lifetime, and oxidation of the surface reduces the surface recombination velocity. However, the minority-carrier lifetime remains below 100 ps for all tested combinations of growth technique and post-growth processing. Significant improvement in SnSsolar cell performance will hinge on finding and mitigating as-yet-unknown recombination-active defects. We describe in detail our methodology for TPC experiments, and we share our data analysis routines in the form freely available software.
DepartmentMassachusetts Institute of Technology. Department of Chemistry; Massachusetts Institute of Technology. Department of Materials Science and Engineering; Massachusetts Institute of Technology. Department of Mechanical Engineering
Journal of Applied Physics
American Institute of Physics (AIP)
Jaramillo, R., Meng-Ju Sher, Benjamin K. Ofori-Okai, V. Steinmann, Chuanxi Yang, Katy Hartman, Keith A. Nelson, Aaron M. Lindenberg, Roy G. Gordon, and T. Buonassisi. “Transient Terahertz Photoconductivity Measurements of Minority-Carrier Lifetime in Tin Sulfide Thin Films: Advanced Metrology for an Early Stage Photovoltaic Material.” Journal of Applied Physics 119, no. 3 (January 21, 2016): 035101.
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