Angle-dependent photocurrent response of pyramid-textured silicon

Abstract

Surface-texturing represents an effective way for improving efficiency in silicon devices, such as light absorbers, photodetectors, and solar cells. In this paper, we examine the angular property of photocurrent response in surface-textured silicon. We characterize photocurrent spectra of both pyramid-textured silicon and un-etched flat silicon at different incident angles for comparison. Our spectral measurements indicate that pyramid-textured silicon exhibits an overall dramatic decrease in the photocurrent response within the wavelength range of 1–1.18 µm at larger incident angles for both s and p polarizations. This angular property is different for un-etched flat silicon, whose photocurrent decreases in a less angle-sensitive manner for s polarization and increases first and then decreases with the incident angle for p polarization as correlated with light reflectance with a characteristic Brewster’s angle. The absence of Brewster’s angle effect in the photocurrent response of pyramid-textured silicon is in agreement with our reflectance simulations. These results help understand the fundamental optical properties induced by surface-texturing in silicon devices.