Infrared Light Absorption Enhancement in Crystalline Silicon Wafer Textured With H2SO4 Solution

In recent years, the formation of microstructures on silicon wafer has gained popularity as a concept for increasing photon trapping and light absorption for optoelectronics applications. This study used three methods to improve infrared light absorption in silicon samples - sample preparation, Radio Corporation of America (RCA) cleaning, and chemical wet etching. The solutions used for Radio Corporation of America (RCA) clean were water (H2O), Ammonium hydroxide (NH4OH), hydrogen perioxide (H2O2), Hydrofluoric acid (H.F.). Three silicon wafers with a 1cm2 orientation were cut and cleaned using RCA, and then surface-textured using a wet chemical procedure by etching into different chemical solutions of Sulfuric acid (H2SO4) of the same concentration. The wafers were removed at different etching time intervals (5, 10, 15 minutes) and analysed using an infrared spectrometer with Fourier transformation (FTIR) to study the absorptions of light. A mean absorbance of 0.9801 a.u, 0.9845 a.u and 0.977 a.u for 5, 10 and 15 minutes of texturization was obtained. The results showed a wafer that was etched by H2SO4 solution for 10 minute as the most enhanced silicon wafer for I.R light absorption. Hence, it is recommended to texture a silicon wafer for a period of 10 minutes in H2SO4 solution for better absorption.