Formation of silicon nanocrystals in SiN x film on PET substrates using femtosecond laser pulses

Korchagina, T.T.; Володин, В. А.; Попов, А. А.; Khorkov, K. S.; Gerke, M. N.

doi:10.1134/s1063785011070091

Cited by 5 publications

(3 citation statements)

References 10 publications

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“…Using the data on the density of electrons excited to the conduction band, the local temperature increase ∆T = T − T 0 (T 0 = 300 K is the initial sample temperature) of germanium after the action of ultrafast laser pulses can be evaluated based on the energy balance equation as c p ρ∆T = n e E g + E e av (7) where c p , ρ, and E e av are the heat capacity of germanium, atomic density, and the average energy of free electrons, respectively. E e av is considered here to be ~2 eV, which is reasonable for the near-melting regime of ultrashort laser excitation [30], c p = 330 J/(kg K) [31]; ρ = 5.15 g/cm 3 [32].…”

Section: Annealing Mechanismsmentioning

confidence: 99%

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Ultrafast Infrared Laser Crystallization of Amorphous Ge Films on Glass Substrates

Cheng,

Bulgakov,

Bulgakova

et al. 2023

Micromachines

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Amorphous germanium films on nonrefractory glass substrates were annealed by ultrashort near-infrared (1030 nm, 1.4 ps) and mid-infrared (1500 nm, 70 fs) laser pulses. Crystallization of germanium irradiated at a laser energy density (fluence) range from 25 to 400 mJ/cm2 under single-shot and multishot conditions was investigated using Raman spectroscopy. The dependence of the fraction of the crystalline phase on the fluence was obtained for picosecond and femtosecond laser annealing. The regimes of almost complete crystallization of germanium films over the entire thickness were obtained (from the analysis of Raman spectra with excitation of 785 nm laser). The possibility of scanning laser processing is shown, which can be used to create films of micro- and nanocrystalline germanium on flexible substrates.

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Section: Annealing Mechanismsmentioning

confidence: 99%

“…Not all flexible substrates can withstand such temperatures. With PLA, it is possible to use very nonrefractory, and therefore inexpensive and flexible, substrates, since the substrates are virtually unheated during annealing [7].…”

Section: Introductionmentioning

confidence: 99%

Ultrafast Infrared Laser Crystallization of Amorphous Ge Films on Glass Substrates

Cheng,

Bulgakov,

Bulgakova

et al. 2023

Micromachines

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“…However bulk phases and thin films are known to have other crystallization mechanisms. In earlier experiments [16,17] amorphous silicon films [16] and silicon nanoparticles in a matrix [17] crystallized as a result of pulse femtosecond laser heating. Obviously this crystallization method can be used in phase change memory cells consisting of silicon nanoparticle arrays.…”

Section: Introductionmentioning

confidence: 98%

Outlooks for development of silicon nanoparticle memory cells

Talyzin¹,

Samsonov²

2019

MoEM

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Phase change memory is based on changes in the optical, electrical or other properties of materials during phase transitions, e.g. an amorphous to crystalline transition. Currently existing and potential applications of this memory are primarily based on multicomponent alloys of metals and semiconductors. However single-component nanoparticles including Si ones are also of interest as promising nanosized memory cells. The potential for developing this type of memory cells is confirmed by the fact that the optical absorption index of bulk amorphous silicon is of the same order of magnitude as that of crystalline silicon. Certainly this phenomenon can hardly be implemented with a single nanoparticle the size of which is within light wavelength. Using molecular dynamics and the Stillinger-Weber potential we have studied the regularities of melting and the conditions of crystallization of silicon nanoparticles containing within 105 atoms. We have shown that cooling of nanosized silicon drops at a 0.2 TK/s rate or higher rates causes their amorphous transition whereas single-component nanosized metallic drops crystallize in molecular dynamics experiments even at a 1 TK/s rate. Further heating of amorphous silicon nanoparticles containing above 5 ∙ 104 atoms causes their crystallization in a specific temperature range from 1300 to 1400 K. We have concluded that there is a possibility of developing phase change memory cells on the basis of the above phase transitions. An amorphous transition of a nanoparticle can be achieved by its melting and further cooling to room temperature at a 0.2 TK/s rate whereas a crystalline transition, by its heating to 1300–1400 K at a 0.2 TK/s rate followed by cooling. Results of molecular dynamics experiments suggest there is a minimum silicon nanoparticle size for which the development of phase change memory cells becomes theoretically impossible at a given temperature change rate. For a 0.2 TK/s temperature change rate this minimum size is 12.4 nm (number of atoms approx. 5 ∙ 104).

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Origin of visible photoluminescence from Si-rich and N-rich silicon nitride films

et al. 2017

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Formation of silicon nanocrystals in SiN x film on PET substrates using femtosecond laser pulses

Cited by 5 publications

References 10 publications

Ultrafast Infrared Laser Crystallization of Amorphous Ge Films on Glass Substrates

Ultrafast Infrared Laser Crystallization of Amorphous Ge Films on Glass Substrates

Outlooks for development of silicon nanoparticle memory cells

Origin of visible photoluminescence from Si-rich and N-rich silicon nitride films

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