Microstructure and optical properties of free-standing porous silicon films: Size dependence of absorption spectra in Si nanometer-sized crystallites
Year: 1993
Type: article
Abstract: We have studied the microstructure and optical properties of free-standing porous Si thin films fabricated by electrochemical anodization. Raman-spectroscopy and transmission-electron-microscopy examinations show that Si crystallite spheres with diameters of several nanometers are dispersed in the amorphous phase. The blueshift of the optical-absorption spectrum is observed for decreasing average diameter of the Si crystallites. However, there is no clear size dependence of the peak energy of the broad photoluminescence (PL) spectrum. Spectroscopic analysis strongly suggests that the photogeneration of carriers occurs in the c-Si core, whose band gap is modified by the quantum-confinement effect, while the strong PL comes from the near-surface region of small crystallites.
Institutions: University of Tsukuba, Nippon Steel (Japan)
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2088069779