Application of Nd:YAG Laser in Semiconductors’ Nanotechnology

Medvíd, A.; Mycko, Aleksandr; Onufrijevs, Pāvels; Daukšta, Edvīns

doi:10.5772/37093

Cited by 3 publications

(2 citation statements)

References 37 publications

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“…Possibility of wide application of GBG structure in optoelectronics devices was shown [2], for example, in a photodetector possessing both properties: it can be of the bolometric type with "open window" on top of cones or with a selective spectral sensitivity depending on light propagation direction; in a light source gradually changing the emitted wavelength depending on zcoordinate like rainbow. Understanding of the mechanism of quantum cones formation in semiconductors by laser radiation is a very important task for physics and nanotechnology.…”

Section: Introductionmentioning

confidence: 99%

Two-stage model of quantum cones formation on a surface of semiconductors by laser radiation

Medvíd

Onufrijevs

Daukšta

2013

2013 13th IEEE International Conference on Nanotechnology (IEEE-NANO 2013)

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A new elaborated laser method for quantum cones formation in elementary semiconductors Si and Ge and their solid solutions is reported. A cone possesses unique properties: a small cone is a quantum dot and a long one is a quantum wire with the gradually decreasing diameter from the base till the top of the cone. Everywhere radius of cone is equal or less than Bohr' radius of electron or exciton Quantum confinement effect (QCE) takes place. Properties of quantum cones using atomic force microscope (AFM), scattering electron microscope (SEM), photoluminescence (PL) and Raman spectroscopy were studied. Unique visible PL spectrum from the surfaces with quantum cones was found and is explained by QCE. A "red" shift of Raman spectra in Ge is a good evidence of the phonon QCE in quantum cones. Asymmetry of PL spectra of the irradiated SiO 2 /Si structure is explained by formation graded band gap structure due to QCE in quantum cones with a graded decrease of diameter toward the top of cone. Two-stage model of quantum cones formation is proposed: Laser Redistribution of Atoms and Selective Laser Annealing. The first stage is characterized by formation of heterostructures such as Ge/Si due to drift of Ge atoms toward the irradiated surface of the sample in the gradient of temperature. New Ge phase is formed at the end of the process. Ge atoms are localized at the surface of Si like a thin film. The second stage is characterized by formation of quantum cones on the irradiated surface of a semiconductor by selective laser heating of the top layer with following mechanical plastic deformation of the layer as a result of relaxation of the mechanical compressive stress arising between these layers due to mismatch of their crystal lattices and selective laser heating. For the first time the possibility of graded band gap 1D structure formation in elementary semiconductors was shown.

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Section: Introductionmentioning

confidence: 99%

Two-stage model of quantum cones formation on a surface of semiconductors by laser radiation

Medvíd

Onufrijevs

Daukšta

2013

2013 13th IEEE International Conference on Nanotechnology (IEEE-NANO 2013)

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“…Quantum dot transforms into a quantum wire with gradually decreasing diameter from the base until the tip of the cone. This is a unique system which has wide technical applications, -for example, 1D-graded bandgap structure in elementary semiconductor is a photodetector with “bolometric” or selective type of photosensitivity, depending on irradiation side [7]. …”

Section: Introductionmentioning

confidence: 99%

Two-stage model of nanocone formation on a surface of elementary semiconductors by laser radiation

et al. 2012

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In this work, we study the mechanism of nanocone formation on a surface of elementary semiconductors by Nd:YAG laser radiation. Our previous investigations of SiGe and CdZnTe solid solutions have shown that nanocone formation mechanism is characterized by two stages. The first stage is characterized by formation of heterostructure, for example, Ge/Si heterostructure from SiGe solid solutions, and the second stage is characterized by formation of nanocones by mechanical plastic deformation of the compressed Ge layer on Si due to mismatch of Si and Ge crystalline lattices. The mechanism of nanocone formation for elementary semiconductors is not clear until now. Therefore, the main goal of our investigations is to study the stages of nanocone formation in elementary semiconductors. A new mechanism of p-n junction formation by laser radiation in the elementary semiconductor as a first stage of nanocone formation is proposed. We explain this effect by the following way: p-n junction is formed by generation and redistribution of intrinsic point defects in temperature gradient field – the thermogradient effect, which is caused by strongly absorbed laser radiation. According to the thermogradient effect, interstitial atoms drift towards the irradiated surface, but vacancies drift to the opposite direction – in the bulk of semiconductor. Since interstitials in Ge crystal are of n-type and vacancies are known to be of p-type, a n-p junction is formed. The mechanism is confirmed by the appearance of diode-like current–voltage characteristics after i-Ge irradiation crystal by laser radiation. The mechanism in Si is confirmed by conductivity type inversion and increased microhardness of Si crystal. The second stage of nanocone formation is laser heating up of top layer enriched by interstitial atoms with its further plastic deformation due to compressive stress caused by interstitials in the top layer and vacancies in the buried layer.

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Electron and hole separation in Ge nanocones formed on Si1−xGex solid solution by Nd:YAG laser radiation

Gorb

Korotchenkov

Kuryliuk

et al. 2015

Applied Surface Science

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Application of Nd:YAG Laser in Semiconductors’ Nanotechnology

Cited by 3 publications

References 37 publications

Two-stage model of quantum cones formation on a surface of semiconductors by laser radiation

Two-stage model of quantum cones formation on a surface of semiconductors by laser radiation

Two-stage model of nanocone formation on a surface of elementary semiconductors by laser radiation

Electron and hole separation in Ge nanocones formed on Si1−xGex solid solution by Nd:YAG laser radiation

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