Photoluminescence and formation mechanism of chemically etched silicon

Abstract

Room-temperature photoluminescence (PL) from Si chemically etched (CE) in HF-HNO3-based solution has been observed. Scanning electron microscopy reveals that the etched Si has a surface morphology similar to that of luminescent porous Si fabricated by conventional anodization. PL spectra show an order of magnitude smaller luminescent intensity and a shorter wavelength intensity peak for CE Si. A CE Si thickness limitation was observed. The formation of CE Si can be readily explained by a local anodization model.