Optical and Electronic Properties of Silicon Nanostructures

Advances in the design, synthesis and characterization of nano-materials are important to provide the unprecedented ability to manipulate matter at the most fundamental level. In the present work photo spectrum of bulk silicon and silicon dots have been examined which were deposited on silicon dioxide (for deposition time: 45 and 60 seconds). It is observed that with decrease in the size of the particles, photoluminescence spectra have been blue shifted and different peaks are obtained corresponding to different sizes of quantum dots. One peak of them is due to oxide layer (quantum confinement effect) and others are due to broad size distribution of Si nano particles. Sizes of quantum dots have been calculated by local density approximation methods. The estimated size of quantum dots are 2.7, 3.4 and 3.9 nanometer and corresponding energy band gaps are 2.41, 1.98 and 1.77 eV respectively.