Potential well

About: Potential well is a research topic. Over the lifetime, 1430 publications have been published within this topic receiving 30812 citations.

Roles of interfaces in nanostructured silicon luminescence

Abstract: The increasing interest in photonics in the field of communication has led to intense research work on silicon based nanostructures showing efficient photoluminescence. The present paper reports photoluminescence measurements obtained at room temperature in silicon-rich-silica-silica multilayers grown by reactive magnetron sputtering. The silicon nanograin size is controlled via the silicon layer thickness which can be monitored with high accuracy. We aim to develop a comprehensive understanding of the combined roles played by the quantum confinement effect through the silicon grain size and the existence of an interfacial region between the grain and the surrounding silica matrix. Two bands of photoluminescence are displayed in the 600 nm-900 nm range and correspond to the bands previously observed at 2 K. Their origin is demonstrated through a model based on the solution of the Schrodinger equation of the exciton wavefunction in a one-dimension geometry corresponding to the growth direction of the multilayers. The silicon layer as well as the Si-SiO2 interface thicknesses are the key parameters of the photoluminescence features.

Nonlinear optical properties of cobalt and iron doped CdSe nanoparticles using Z-scan technique

Abstract: The present work aims at the synthesis of pure, Cobalt (Co) and Iron (Fe) doped CdSe nanoparticles by the wet chemical method. The optical properties of synthesized nanoparticles have been characterized by X-ray diffraction (XRD), UV–vis spectroscopy to find the optical direct band gap and estimation of particle size by using Debye–Scherrer formula and HRTEM. The nonlinear optical properties such as nonlinear absorption co-efficient, nonlinear refraction co-efficient and third order nonlinear susceptibility χ (3) are investigated. The calculations have been performed with the help of Z-scan experimental set-up using Nd: YAG laser emitting 532 nm, 5 ns laser pulses with intensity maintained at 2.296 TW/cm 2 . The nanoparticles clearly exhibit a negative value of nonlinear refraction, which is attributed to the two photon absorption and free carrier absorption. Further the optical limiting behavior is determined (figure of merit (FOM)). The presence of RSA in these nanoparticles makes them a potential material for the development of optical limiter.

The self-consistent calculation of a spherical quantum dot: A quantum genetic algorithm study

Abstract: In this study, we have calculated the subband energy level, potential profile, and the corresponding wavefunction and chemical potential for different temperatures and donor concentrations in a spherical quantum dot self-consistently. We have also investigated the effect of exchange-correlation potential on the energy levels. In addition, we have checked the applicability of quantum genetic algorithm to a realistic self-consistent quantum dot problem. In all computations, the penetration of wavefunction to the barrier region is taken into account.