Electrore¯ectance study of macroporous silicon surfaces

The surfaces of a number of samples of macroporous silicon were characterized by electrore¯ectance spectroscopy. Specimens with pore diameters of 1±15 mm and pore depths from 15 to 80 mm were prepared by electrochemical etching with different values of current and bias. Etching enriches n-type silicon with majority carriers, and the existence of an intrinsic electric ®eld is demonstrated. The intrinsic ®eld develops due to the growth of an oxide layer on the pore walls. Correlation between the etching current and physical characteristics such as the phenomenological broadening parameter G, the magnitude of the intrinsic electric ®eld, and the electro-optic energy is shown. # 2001 Elsevier Science B.V. All rights reserved.