Photoelectrochemical Analysis of Tin Selenide (SnSex) Thin Films Formed Using Electrochemical Atomic Layer Deposition (E-ALD)

Abstract

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. 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.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.