Effects of uniaxial strain on electron effective mass and tunneling capability of direct gap Ge1−<i>x</i>Sn<i>x</i> alloys

Liu, Lei; Liang, Renrong; Wang, Jing; Xu, Jun

doi:10.1063/1.4939816

Cited by 5 publications

(1 citation statement)

References 35 publications

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“…The enhancement of m * could be related to the stress in the films. 37 As displayed in Fig. S3b in the ESI, † as the thickness increases, the lattice parameters tend to relax, approaching bulk values for thicknesses close to 200 nm.…”

Section: (Ii) Thickness Analysis: Study Of Thermoelectric Properties ...mentioning

confidence: 90%

Enhanced thermoelectric properties of lightly Nb doped SrTiO₃ thin films

et al. 2019

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Section: (Ii) Thickness Analysis: Study Of Thermoelectric Properties ...mentioning

confidence: 90%

Enhanced thermoelectric properties of lightly Nb doped SrTiO₃ thin films

et al. 2019

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Formation of uniaxial strained Ge via control of dislocation alignment in Si/Ge heterostructures

et al. 2018

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Uniaxially strained Ge/SiGe heterostructures are fabricated by selective ion implantation technique, where dislocation alignments are highly controlled by the local defect introduction. Firstly, ion-implantation-defects are selectively induced into a Ge substrate, followed by the growth of a SiGe buffer layer. As a result, the SiGe on the implanted region is largely strain-relaxed due to the defects acting as dislocation sources. In contrast, it is demonstrated that anisotropic strain relaxation takes place in the SiGe on the unimplanted region, leading to the uniaxial strained SiGe. A strained Ge layer is pseudomorphically grown on the SiGe buffer and the same strain states are observed for the Ge layer. It is found that misfit dislocations generated at the interface between the SiGe layer and the Ge substrate are aligned along only one direction. These one-directional dislocations are an origin of the uniaxial strain relaxation. Moreover, effects of ion-implantation stripe-pattern widths on the strain states are investigated. With the implanted line width increasing, the anisotropy of the strain in the unimplanted region is enhanced. From these results, it can be said that this technique opens a route to engineer dislocation alignments and anisotropic strain in semiconductor hetero structures toward high performance novel devices.

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Extraction of eight-band k⋅p parameters from empirical pseudopotentials for GeSn

Liu

Yen

2019

Journal of Applied Physics

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We extract the parameters for the eight-band k⋅p model for Ge1−xSnx (x≤0.15) from the calculation of the nonlocal empirical pseudopotential method with the modified virtual crystal approximation. The atomic pseudopotential form factors of Ge are improved such that the calculated Ge band structure has the commonly accepted bandgap and effective masses. The improved Ge parameters are used in proper interpolation to derive the parameters of GeSn for empirical pseudopotential calculation. The calculated band structures suggest that the Ge1−xSnx alloys exhibit a transition between an indirect bandgap semiconductor and a direct one at Sn composition xc=0.071. From the calculation, we extract the bandgap, the split-off energy, the interband momentum matrix element, and the effective masses of Ge1−xSnx (x≤0.15) as functions of x. From these results, we further derive the parameters used in the eight-band k⋅p model. These parameters are well expressed in quadratic form. The k⋅p model with the extracted parameters can give an interband tunneling current in a “pin” diode that is consistent with the current calculated by the empirical pseudopotential method.

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Effects of uniaxial strain on electron effective mass and tunneling capability of direct gap Ge1−xSnx alloys

Cited by 5 publications

References 35 publications

Enhanced thermoelectric properties of lightly Nb doped SrTiO₃ thin films

Enhanced thermoelectric properties of lightly Nb doped SrTiO₃ thin films

Formation of uniaxial strained Ge via control of dislocation alignment in Si/Ge heterostructures

Extraction of eight-band k⋅p parameters from empirical pseudopotentials for GeSn

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Effects of uniaxial strain on electron effective mass and tunneling capability of direct gap Ge1−xSnx alloys

Cited by 5 publications

References 35 publications

Enhanced thermoelectric properties of lightly Nb doped SrTiO3 thin films

Enhanced thermoelectric properties of lightly Nb doped SrTiO3 thin films

Formation of uniaxial strained Ge via control of dislocation alignment in Si/Ge heterostructures

Extraction of eight-band k⋅p parameters from empirical pseudopotentials for GeSn

Contact Info

Product

Resources

About

Enhanced thermoelectric properties of lightly Nb doped SrTiO₃ thin films

Enhanced thermoelectric properties of lightly Nb doped SrTiO₃ thin films