Low-temperature, solution-based routes to nanocrystalline InS powders and thin films

We have developed several solution-based preparations for nanocrystalline orthorhombic InS, which is a mid band gap semiconductor (2.44 eV) with potential applications in photovoltaics. Various reagents were used as indium (t-Bu₃In, t-Bu₂InCl) and sulfur (H₂S, (TMS)₂S) sources. Growth of crystalline powders was dependent upon the addition or in-situ generation of indium metal. These reactions represent the first reported use of a Solution-Liquid-Solid (SLS) mechanism by which semiconductors are grown from a molten metal flux for a system other than the III-V family of semiconductors. The studies on powder preparations were used to develop a new, low-temperature (185 °C) chemical-bath process for depositing a polycrystalline InS thin film. The film was deposited from a solution of t-Bu₃In and elemental sulfur onto an indium-coated fused-silica substrate; the indium film acted as the crystallization medium.