Visible photoluminescence from porous Si formed by annealing and chemically etching amorphous Si

Abstract

We have studied the visible photoluminescence (PL) and microstructure of amorphous Si (a-Si) after annealing and etching. The a-Si layers were grown on (100)Si substrates and partially crystallized by annealing between 550–1150 °C. Porous Si layers (PSLs) were then produced by etching in HF-HNO3. While no visible PL was observed from unannealed and etched a-Si, visible PL was detected after annealing and etching. The observation of visible PL after etching coincided with the observation of Si microcrystallites in the annealed layer. The results suggest that an initial crystalline structure is important for fabricating luminescent PSLs.