Séminaire LMGP - 15/10/2019 - Andrii Voznyi

Andrii Voznyi
Postdoctoral researcher

Abstract
Thin film photovoltaics based on tin monosulfide (SnS) is currently under intense research, as SnS is considered a promising, earth abundant and non-toxic replacement for the absorber layer in thin film solar cells based on the traditional CdTe, CuInSe2 (CIS), or Cu(In,Ga)(S,Se)2 (CIGSS) absorbers. Meanwhile, tin sulfide may also crystallise in a SnS2 phase with a higher band gap of 2.2-2.8 eV. This band gap makes SnS2 particularly attractive for application as the n-type buffer layer in the heterojunction solar cells. This talk focuses mainly on characterization and post-growth treatment of SnxSy thin films obtained by close spaced sublimation (CSS) and atomic layer deposition (ALD) techniques, and application of such layers in heterojunction solar cells. In particular, the ability to control the SnxSy crystal phases, morphology, optical and electrical properties by both variation of growth conditions and type of the substrate will be discussed. Non-traditional approaches were also applied to fabricate the pure-phase SnS thin films and two-layer n-SnS2-p-SnS heterojunction structures, including thermal vacuum annealing and laser irradiation of initial single-phase SnS2 films, respectively. Lastly, the photovoltaic behavior of SnS-based heterojunctions in various stack configurations, using different back contact materials, buffer layer compositions, SnS crystal phases and thicknesses of buffer and absorber layers will be briefly discussed.