Optical properties of quantum cones formed in semiconductors by laser radiation
Journal of Physical Chemistry & Biophysics

Journal of Physical Chemistry & Biophysics
Open Access

ISSN: 2161-0398

+44 20 3868 9735

Optical properties of quantum cones formed in semiconductors by laser radiation

3rd International Conference and Exhibition on Lasers, Optics & Photonics

September 01-03, 2015 Valencia, Spain

Arturs Medvids and Pavels Onufrijevs

Riga Technical University, Latvia

Posters-Accepted Abstracts: J Phys Chem Biophys

Abstract :

Nowadays, nanostructures are one of the most investigated objects in semiconductor physics, especially due to Quantum confinement effect (QCE) in quantum dots (0D), quantum wires (1D) and quantum wells (2D). A new laser technology elaborated for quantum cones formation in semiconductors is reported. A cone possesses the following unique properties: A small cone is a quantum dot â?? 0D and a long one is a quantum wire â?? 1D with the gradually decreasing diameter from the base till the top of the cone. Such quantum cone luminesces like rainbow. Quantum cones on the surface of elementary semiconductors Si and Ge single crystals, and on a surface of SiGe and CdZnTe solid solutions were formed by fundamental frequency and second harmonic of Nd:YAG laser radiation. Strong change of the optical properties of the semiconductors after irradiation by Nd:YAG laser are explained by the presence of QCE in quantum cones. â??Blue shiftâ? of photoluminescence spectra and â??red shiftâ? of phonon LO line in Raman spectrum are explained by exciton and phonon QCE in quantum cones, correspondently. Asymmetry of the photoluminescence band in the spectrum of Si quantum cones is explained by 1D graded band gap structure. Experimental data on quantum cones formation on a surface of Si, Ge and their solid solution and CdZnTe crystal and their optical properties are presented. Two-stage mechanism of quantum conesâ?? formation on a surface of the semiconductors is proposed. The first stage of the mechanism is characterized by the formation of a thin strained top layer, due to redistribution of point defects in temperaturegradient field induced by laser radiation. The second stage is characterized by mechanical plastic deformation of the stained top layer leading to arising of quantum cones due to heating up of the top layer. Formed quantum cones can be applied for design of third generation solar cells, Si white light emitting diode, photon detector with selective or â??bolometerâ? type spectral sensitivity and Si tip for field electron emitting with low work function.

Biography :

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