High Optical Absorption of Indium Sulfide Nanorod Arrays Formed by Glancing Angle Deposition

Indium (III) sulfide has recently attracted much attention due to its potential in optical sensors as a photoconducting material and in photovoltaic applications as a wide direct bandgap material. On the other hand, optical absorption properties are key parameters in developing highly photosensitive photodetectors and high efficiency solar cells. We show that indium sulfide nanorod arrays produced by glancing angle deposition techniques have superior absorption and low reflectance properties compared to conventional flat thin film counterparts. We observed an optical absorption value of approximately 96% for nanorods, in contrast to 80% for conventional amorphous-to-polycrystalline thin films of indium sulfide. A photoconductivity response was also observed in the nanorod samples, whereas no measurable photoresponse was detected in conventional thin films. We give a preliminary description of the enhanced light absorption properties of the nanorods by using Shirley-George Model that predicts enhanced diffuse scattering and reduced reflection of light due the rough morphology.