Near-unity below-band gap absorption by microstructured silicon


C. Wu, C. H. Crouch, L. Zhao, J. E. Carey, R. J. Younkin, J. A. Levinson, E. Mazur, R. M. Farrel, P. Gothoskar, and A. Karger. 2001. “Near-unity below-band gap absorption by microstructured silicon.” Appl. Phys. Lett., 78, Pp. 1850–1852. Publisher's Version


We increased the absorptance of light by silicon to approximately 90% from the near ultraviolet (0.25 m) to the near infrared (2.5 m) by surface microstructuring using laser-chemical etching. The remarkable absorptance most likely comes from a high density of impurities and structural defects in the silicon lattice, enhanced by surface texturing. Microstructured avalanche photodiodes show significant enhancement of below-band gap photocurrent generation at 1.06 and 1.31 m, indicating promise for use in infrared photodetectors.
Last updated on 07/24/2019