Optimizing inverted pyramidal grating texture for maximum photoabsorption in thick to thin crystalline silicon photovoltaics

We use the wave optical approach to optimize the front surface inverted pyramidal grating texture on 2 to 400 μm thick crystalline silicon in order to derive the maximum photocurrent density from the cell. We identify a “one size fits all” front grating periodicity of 1000 nm for c-Si absorbing layer configured with a back surface reflector that maximizes the absorption of normally incident AM1.5g solar spectrum irrespective of the layer thickness. With the identification of such universal inverted pyramidal grating texture, a common texturing process can be developed for high-efficiency devices on thick to thin c-si. Furthermore, our studies show that the photocurrent decreases by 0.02 mA/cm² with every nanometer increase in the width of the flat region (mesa) between inverted pyramids in the optimum texture. The decrease in photocurrent due to reflection from the mesas can be recovered with the addition of an antireflective coating of optimum thickness of 80 nm and refractive index ~ 2.1.