Growth of antimony selenide solar absorber on micro textured substrates for efficient light trapping and enhanced optical absorption

We propose a method for substrate surface texturing with shallow micro structures (such as cylinders) made up of cross-linked SU8 2005 photoresist on glass substrates for conformal growth of thin films of functional materials. In this work, the textured substrates were used for the growth of antimony selenide (Sb2Se3) solar absorber and its properties were studied in comparison with films on plain glass substrates. Cross-linked SU8 2005 structures, i.e., an array of equally spaced cylinders having the dimensions of 100 µm/70 µm/40 µm diameter and 5 µm height, were introduced over an area of 20 mm × 20 mm on glass substrates via optical lithography process. Thin films of Sb2Se3 were grown above the textured surface using e-beam evaporation covering the glass-like resist structures underneath. Optical microscopy, scanning electron microscope (SEM) and optical profiler analyses confirm the morphological integrity of the Sb2Se3 absorber layer grown on textured substrates. Raman spectra were collected on plain and textured samples to probe the structural uniformity. The optical absorbance data of Sb2Se3 thin films grown on plain and periodically textured glass substrates were investigated using UV–Vis-NIR spectroscopy to study the effects of substrate texturing.