Making Record-efficiency SnS Solar Cells by Thermal Evaporation and Atomic Layer Deposition

TitleMaking Record-efficiency SnS Solar Cells by Thermal Evaporation and Atomic Layer Deposition
Publication TypeJournal Article
Year of Publication2015
AuthorsJaramillo, R, Steinmann, V, Yang, C, Hartman, K, Chakraborty, R, Poindexter, JR, Castillo, MLizet, Gordon, R, Buonassisi, T
JournalJove-Journal of Visualized Experiments
Issue99
Paginatione52705
Date Published2015/05//
Abstract

Tin sulfide (SnS) is a candidate absorber material for Earth-abundant, non-toxic solar cells. SnS offers easy phase control and rapid growth by congruent thermal evaporation, and it absorbs visible light strongly. However, for a long time the record power conversion efficiency of SnS solar cells remained below 2%. Recently we demonstrated new certified record efficiencies of 4.36% using SnS deposited by atomic layer deposition, and 3.88% using thermal evaporation. Here the fabrication procedure for these record solar cells is described, and the statistical distribution of the fabrication process is reported. The standard deviation of efficiency measured on a single substrate is typically over 0.5%. All steps including substrate selection and cleaning, Mo sputtering for the rear contact (cathode), SnS deposition, annealing, surface passivation, Zn(O,S) buffer layer selection and deposition, transparent conductor (anode) deposition, and metallization are described. On each substrate we fabricate 11 individual devices, each with active area 0.25 cm(2). Further, a system for high throughput measurements of current-voltage curves under simulated solar light, and external quantum efficiency measurement with variable light bias is described. With this system we are able to measure full data sets on all