Hot carriers and excitation of Si/SiOx interface defect photoluminescence in Si nanocrystallites

In low-dimensional silicon wires and dots, as supposed earlier (Phys. Rev. B 65 (2002) 115313), hot carrier ballistic transport towards the Si/SiOx interface can enhance the excitation of oxide defect-related photoluminescence (PL) bands. This article presents new experimental results supporting the role of ballistic transport in bright visible photoluminescence of silicon nano-crystallites. The intensity dependences of the "red" and "orange" photoluminescence bands on excitation light wavelengths, diameters of Si nano-crystallites and surface area of porous layers have been analysed. The models of optical transitions at the excitation of both PL bands are discussed as well. (C) 2003 Elsevier B.V. All rights reserved.