The topography of laser-irradiated germanium

Emmony, D. C.; Phllips, N J; Toyer, J H; Willis, Lucas

doi:10.1088/0022-3727/8/13/008

Cited by 20 publications

(3 citation statements)

References 2 publications

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“…The new feature of the proposed model is the inclusion of thermally induced plastic effects. It was shown that the increased size of the affected area due to heating under the laser irradiation conditions used, may not be interpreted via other conventional physical mechanisms, such as melting 51,52 or ablation 26 , which do not sufficiently quantify the measured dimensions of the resulting spot size. Although the proposed scenarios may adequately describe, at least qualitatively, the underlying physical processes, the assumption that the related phenomena are confined in a region inside the laser beam spot area underestimates the contribution of the thermal stress deformation.…”

Section: Resultsmentioning

confidence: 99%

Thermoplastic deformation of silicon surfaces induced by ultrashort pulsed lasers in submelting conditions

Tsibidis

Stratakis

Aifantis

2012

Journal of Applied Physics

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A hybrid theoretical model is presented to describe thermoplastic deformation effects on silicon surfaces induced by single and multiple ultrashort pulsed laser irradiation in submelting conditions. An approximation of the Boltzmann transport equation is adopted to describe the laser irradiation process. The evolution of the induced deformation field is described initially by adopting the differential equations of dynamic thermoelasticity while the onset of plastic yielding is described by the von Mise's stress. Details of the resulting picometre sized crater, produced by irradiation with a single pulse, are discussed as a function of the imposed conditions and thresholds for the onset of plasticity are computed. Irradiation with multiple pulses leads to ripple formation of nanometre size that originates from the interference of the incident and a surface scattered wave. It is suggested that ultrafast laser induced surface modification in semiconductors is feasible in submelting conditions, and it may act as a precursor of the incubation effects observed at multiple pulse irradiation of materials surfaces.

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Section: Resultsmentioning

confidence: 99%

Thermoplastic deformation of silicon surfaces induced by ultrashort pulsed lasers in submelting conditions

Tsibidis

Stratakis

Aifantis

2012

Journal of Applied Physics

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“…T m is the to solid is 6%. 21,28 The solid curve in Fig. 5(b) shows the simulated spectrum calculated using the phonon confinement model after accounting for stress originating from the interface energy, solidification expansion, and differential thermal expansion.…”

Section: Raman Spectroscopymentioning

confidence: 99%

Structural properties of Ge nanocrystals embedded in sapphire

Sharp

et al. 2006

Journal of Applied Physics

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Isotopically pure 74 Ge nanocrystals were formed in a sapphire matrix by the ion beam synthesis method. In contrast to those embedded in amorphous silica, sapphire-embedded nanocrystals are clearly faceted and are preferentially oriented with respect to the crystalline matrix. In situ transmission electron microscopy of heated samples reveals that the nanocrystals melt at 955 °C ± 15 °C, very near to the bulk Ge melting point. Raman spectra indicate that the sapphireembedded Ge nanocrystals are under compressive stress in the range of 3 -4 GPa. The 2 magnitude of the stress is consistent with that expected for hydrostatic pressure arising from solidification. Stress relaxation was not observed for sapphire-embedded Ge nanocrystals; this is attributed to the slow self-diffusion rate of the alumina matrix atoms at temperatures below the nanocrystal melting point.

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“…레이저 조사가 종료 되어 용융된 게르마늄이 고체로 재응고될 때, 용융 연 못의 대류와 점성에 의해Fig. 7과같이 원뿔 모양의 hillock이 형성된다[14] . 그러므로 표면 변화가 나타난 곳까지 레이저 조사에 의해 용융온도 이상으로 온도 같이 측정치가 계산치보다 5.9 % 정도 크게 측정되었 으며, 조건 B로 실험한Fig.…”

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Study of Damage in Germanium Optical Window Irradiated by a Near-infrared Continuous Wave Laser

Lee

Shin²,

Kang³

2014

Journal of the Korea Institute of Military Science and Technolo

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The damage in germanium (Ge) optical window irradiated by a near-infrared continuous wave (CW) laser was studied. Laser-induced heating and melting process were surveyed, and the specific laser power and the irradiance time to melt were estimated by numerical simulation. The experiments were also carried out to investigate the macro and micro structure change on Ge window. Results showed that the surface deformation was formed by melting and resolidification process, the damaged surface had a polycrystalline phase, and the transmittance as an optical performance factor in mid-infrared region was decreased. We confirmed that an abnormal polycrystalline phase and surface deformation effect such as hillock formation and roughness increase reduced the transmittance of Ge window and were the damage mechanism of CW laser induced damage on Ge window.

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The topography of laser-irradiated germanium

Cited by 20 publications

References 2 publications

Thermoplastic deformation of silicon surfaces induced by ultrashort pulsed lasers in submelting conditions

Thermoplastic deformation of silicon surfaces induced by ultrashort pulsed lasers in submelting conditions

Structural properties of Ge nanocrystals embedded in sapphire

Study of Damage in Germanium Optical Window Irradiated by a Near-infrared Continuous Wave Laser

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