Berlin 2015 – scientific programme

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DS: Fachverband Dünne Schichten

DS 2: Thin Film Characterisation I: Structure Analysis and Composition

DS 2.7: Talk

Monday, March 16, 2015, 11:15–11:30, H 0111

Growth and Properties of Crystalline Silicon deposited on Glass by Steady-State Solution Growth — •Christian Ehlers, Roman Bansen, Jan Schmidtbauer, Franziska Ringleb, Thomas Teubner, and Torsten Boeck — Leibniz Institute for Crystal Growth, Berlin, Germany

For a thin-film silicon solar cell, only several tens of micrometer of crystalline silicon are needed for sufficient light absorption. Therefore we have developed a two-step process for depositing thin silicon layers on inexpensive glass substrates below the softening point of glass.

In the first step a seed layer of nanocrystalline silicon is formed on the heated glass substrates by two different approaches. Either only silicon is evaporated by physical vapor deposition which subsequently forms a thick nanocrystalline layer, or a metal is co-evaporated which leads to the metal-induced crystallization of nanocrystalline silicon. In the second growth step, a subsequent silicon layer is grown on the initial seed layer by steady-state solution growth from a tin or indium solution.

In comparison to traditional liquid phase epitaxy where the supersaturation of the solution is driven by cooling of the metallic solvent, we employ a steady temperature gradient between the silicon source material and substrate. Therefore, growth conditions are similar to a commercial float glass production-process, which potentially allows for the deposition of silicon in a continuous fashion. The electrical and structural properties of the grown silicon layers are analyzed with regard to their suitability for solar cell device production.