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Krishnamurthy, Srinivasan; Sher, A.; Chen, A.-B.

doi:10.1103/physrevb.33.1026

Cited by 89 publications

(23 citation statements)

References 35 publications

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“…We have used this method to study optical and electronic properties of Hg 0.78 Cd 0.22 Te, In 0.67 Tl 0.33 P, In 0.85 Tl 0.15 As, and In 0.92 Tl 0.08 Sb alloys. 13 In this article, we derive the expressions needed to obtain the AR and the minority carrier lifetimes. All quantities needed to calculate the rates and times are obtained from the underlying HPTB Hamiltonian without resorting to any additional approximations.…”

Section: Introductionmentioning

confidence: 99%

Accurate calculation of Auger rates in infrared materials

Krishnamurthy

Sher

Chen

1997

Journal of Applied Physics

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The Auger recombination rates in small-gap semiconductor alloys are calculated using full band structures with electron–electron interactions in Coulomb and phonon fields. We find that the results are sensitive to band structure details and the calculated minority carrier lifetimes can differ by two orders of magnitude depending on the approximations used to describe the energy bands and wave functions. The full band structure results agree well with experiments in Hg0.78Cd0.22Te. Similar calculations were carried out for lifetimes in In0.67Tl0.33P, In0.85Tl0.15As, and In0.92Tl0.08Sb as a function of temperature. The minority carrier lifetimes in In0.67Tl0.33P and In0.92Tl0.08Sb are shorter than that in Hg0.78Cd0.22Te at all temperatures. However, the low-temperature minority carrier lifetime in In0.85Tl0.15As is an order of magnitude longer than that in Hg0.78Cd0.22Te. Our calculations further suggest a possibility of increasing the lifetimes of minority carriers by decreasing the density of states inside a critical energy and momentum region and also by selecting donors with energies in the gap.

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Section: Introductionmentioning

confidence: 99%

Accurate calculation of Auger rates in infrared materials

Krishnamurthy

Sher

Chen

1997

Journal of Applied Physics

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“…A number of theoretical studies exist for the band structure of the Si x Ge 1--x system using a variety of methods, such as the virtual crystal approximation (VCA) [7], the coherent potential approximation (CPA) [8], the molecular coherent approximation (MCPA) [9] and the non-local pseudopotential method [10]. In particular, Stroud and Ehrenreich [8] presented results of the CPA band structure for Si 0.37 Ge 0.63 and found that the states most significantly broadened lie in the s-like conduction band near G 2 0 .…”

Section: Introductionmentioning

confidence: 99%

“…The calculated values had an almost constant difference of 1.9 eV from the experimental values [4] over most of the concentration range. Krishnamurthy et al [9], using CPA and MCPA, investigated the E 0 , E 0 0 and E 1 critical points (CP) for silicon concentrations x ¼ 0.1, 0.109, 0.25 and 0.5 and found a linear dependence of their energies with the concentration. They also studied the broadening of the E 0 , and E 0 0 CPs for these particular concentrations.…”

Section: Introductionmentioning

confidence: 99%

Calculation of the Electronic Structure and Energy Broadening of SixGe1?x Alloys

Vinga

Theodorou

2001

phys. stat. sol. (b)

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The Haydock recursion method is used to study the electronic structure of the Si x Ge 1--x alloy. The direct energy band gap of this material as a function of silicon concentration is calculated at the critical symmetry points G, X and L. A systematic theoretical study of the alloy's energy broadening, produced by disorder, at the same symmetry points is also presented. It was found that the broadening is significant mainly for the conduction band, while for the valence band it is negligible. The theoretical results are in satisfactory agreement with the reported experimental ones for the entire concentration range.

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“…Because the alloy bandgaps are indirect, the Γ-like state is in resonance with other k points that are degenerate with the Γ state, leading to significant inter-valley coupling. [9] We have recently found that, by a direct calculation using the 27648-atom supercell, for Ga x In 1-x P with x = 0.8 in the indirect bandgap region the A(Γ,E) spectrum shows barely a peak to allow for the identification of the Γ-like state in the alloy. [10] However, for x = 0.5 in the direct bandgap region, the 27648-atom supercell is far from adequate to reveal the intrinsic A(Γ,E) spectrum, because the alloy scattering to the Γ state is very weak.…”

Section: Introductionmentioning

confidence: 99%

“…By calculating A(k,E) throughout the BZ, one can construct an effective band structure for an alloy using a properly defined VCA reference band structure, which has been done for numeral semiconductor alloys: Hg 1-x Cd x Te, [12] Si x Ge 1-x , [9], Ga 0.5 In 0,5 As and ZnSe 0.5 Te 0.5 , [7] and the latest In x Ga 1-x N. [11] It turns out that the most challenging task is to accurately calculate A(Γ,E) for a direct bandgap material, which has never been explicitly calculated using a sufficiently large supercell, but is fundamentally important for the understanding of the alloying effect.…”

Section: Introductionmentioning

confidence: 99%

Global electronic structure of semiconductor alloys through direct large-scale computations for III-V alloys GaxIn1−xP

Zhang

Wang

2011

Phys. Rev. B

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We critically examine two nominally equivalent approaches for treating a random alloy: (1) using one very large supercell as a direct simulation of the alloy, and (2) performing configuration averaging over many smaller supercells; and the common practice using a virtual-crystal as the reference for analyzing the alloy band structure and discussing the electronic transport in the alloy. Specifically, (1) we show that in practice the size of the "very large" supercell depends on the particular property of interest, and the ideal of the configuration averaging is only useful for certain properties; (2) we examine the assumed equivalency by comparing the results of the two approaches in bandgap energy, energy fluctuation, and inter-valley and intra-valley scatterings, and conclude that the two approaches often lead to non-equivalent physics; (3) by using a generalized moment method that is capable of computing the global electronic structure of a sufficiently large supercell (e.g., ~ 260,000 atoms), we are able to obtain the intrinsic broadening of a Γ-like electron state, caused by the "inelastic" intra-valley scattering, in a direct bandgap semiconductor alloy; (4) we demonstrate an efficient way to construct the effective dispersion curves of the alloy, with high accuracy for calculating effective masses and examining anisotropy and nonparabolicity of the dispersion curve; and (5) finally, we discuss the limitation of using virtual crystal approximation as the reference for evaluating the alloy scattering and studying the transport property.2

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Band structures ofSixGe1−
Srinivasan Krishnamurthy
¹
,
A. Sher
²
,
A.-B. Chen
³

Cited by 89 publications

References 35 publications

Accurate calculation of Auger rates in infrared materials

Accurate calculation of Auger rates in infrared materials

Calculation of the Electronic Structure and Energy Broadening of SixGe1?x Alloys

Global electronic structure of semiconductor alloys through direct large-scale computations for III-V alloys GaxIn1−xP

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Band structures ofSixGe1−Srinivasan Krishnamurthy1, A. Sher2, A.-B. Chen3

Cited by 89 publications

References 35 publications

Accurate calculation of Auger rates in infrared materials

Accurate calculation of Auger rates in infrared materials

Calculation of the Electronic Structure and Energy Broadening of SixGe1?x Alloys

Global electronic structure of semiconductor alloys through direct large-scale computations for III-V alloys GaxIn1−xP

Contact Info

Product

Resources

About

Band structures ofSixGe1−
Srinivasan Krishnamurthy
¹
,
A. Sher
²
,
A.-B. Chen
³