Tin selenide is an attractive material for photovoltaic devices as an absorber layer.¹ There are two derivatives: SnSe and SnSe₂. SnSe is a p-type material that exhibits a band gap of 1.0 eV. SnSe₂ is a n-type material with a band gap of 1.6 eV.¹ In this study, tin selenide thin films have been electrochemically deposited using a process known as electrochemical atomic layer deposition (E-ALD). E-ALD uses the phenomenon known as underpotential deposition to deposit an atomic monolayer of each element separately. This process is known as a cycle and is repeated until the desired thickness is achieved.² These films need further optimization for the selection of one species over the other. Initial photolectrochemical studies have shown the current thin film is p-type and is an option for a photocathode for hydrogen production in a photoelectrochemical cell. Further studies will include improving the deposition cycle used to increase the photoresponse of the material and to gain control over the appearance of SnSe or SnSe₂.

1. Subramanian, B; Snajeeviraja, C.; Jayaychandran, M. Review on materials properties Sn(S,Se) compound semiconductors useful for photoelectrochemical solar cells. Electrochem. 2002, 18 (8), 349-366.
2. Stickney, J. L.; Villegas, I.; Suggs, D. W.; Gregory, B. W., Electrochemical Atomic Layer Epitaxy (ECALE). Abstr Pap Am Chem S 1991, 201, 289-Coll.