VISIBLE PHOTOLUMINESCENCE AND ELECTROLUMINESCENCE FROM ELECTROCHEMICALLY FORMED NANOCRYSTALLINE SI THIN-FILM

Visible photo- (PL) and electroluminescence (EL) were observed at room temperature from nanocrystalline Si (nc-Si) thin film; nc-Si was elec trochemically formed in HF aqueous solution from baron doped microcrys talline Si (mu c-Si) deposited by a rf plasma chemical vapor depositio n method on a glass substrate with a SnO2 transparent conductive layer . From the scanning electron microscope images, the ''pore'' structure is not feued on the surface of the nc-Si thin film. PL occurs with a broadband spectrum peaking at an energy around 1.7 eV and its spectral shape resembles that of conventional porous Si made from a crystallin e Si substrate. The dependence of PL intensity on crystalline volume f raction in mu c-Si implies that the quantum size effects operate in th e emission process in nc-Si. Visible EL emission was observed in a p-i -n heterostructured diode consisting of the nc-Si and amorphous layers with the spectral peak energy of 1.8 eV. (C) 1996 American Institute of Physics.