First-principles Analysis of Indirect-to-Direct Band Gap Transition of Ge Under Tensile Strain

Hoshina, Yoichiro; Iwasaki, Kazuma; Yamada, Akira; Konagai, M.

doi:10.7567/ssdm.2008.f-6-1

Cited by 2 publications

(2 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In particular it is possible to modify the position of the conduction band (CB) minima and valence band (VB) maxima thanks to strain, even leading to a transition from direct to indirect character of the band gaps. This has been shown for bulk Ge [7,8], and more recently in low dimensional transition metal dichalcogenides [9][10][11]. In the case of h-BN , different experiments were performed to study the effect of an hydrostatic pressure on the structural, vibrational [12,13] and optical properties [14].…”

Section: Introductionmentioning

confidence: 98%

Excitons under strain: light absorption and emission in strained hexagonal boron nitride

Lechifflart,

Paleari,

Attaccalite

2021

Preprint

View full text Add to dashboard Cite

Hexagonal boron nitride is an indirect band gap material with a strong luminescence intensity in the ultraviolet. This luminescence originates from bound excitons recombination assisted by different phonon modes. The coupling between excitons and phonons is so strong that the resulting light emission is as efficient as the one of direct band gap materials. In this manuscript we investigate how uniaxial strain modifies the properties of this material. In particular we study how the electronic band structure and optical response change with strain. Our results are important for experiments that directly probe h-BN under strain or use it as substrate for other 2D material with a lattice mismatch.

show abstract

Section: Introductionmentioning

confidence: 98%

Excitons under strain: light absorption and emission in strained hexagonal boron nitride

Lechifflart,

Paleari,

Attaccalite

2021

Preprint

View full text Add to dashboard Cite

show abstract

“…At present, the direct band gap technique of GeSn alloying has the problems of low solid solubility of Sn in Ge (about 1%), serious surface segregation, and incompatibility with the Si process, and the tensile strain-induced direct band gap Ge technology has the defects of difficult process realization, many crystal defects, poor quality, and so on [24]. To this end, this paper uses a direct band gap Ge implementation method compatible with the Si process-etching around the Ge epitaxial layer on the Si substrate and selectively filling Si 1− x Ge x to properly introduce the biaxial tensile stress to realize the conversion of the Ge band gap type [25]. e structure of this method is shown in Figure 4, where d, T, and L correspond to the Ge mesa region width, Si 1− x Ge x stressor thickness, and the distance between adjacent mesas, respectively.…”

Section: Introductionmentioning

confidence: 99%

Finite Element Stress Model of Direct Band Gap Ge Implementation Method Compatible with Si Process

Xue

Song

Rong-Xi

2019

Advances in Condensed Matter Physics

View full text Add to dashboard Cite

As an indirect band gap semiconductor, germanium (Ge) can be transformed into a direct band gap semiconductor through some specific modified methods, stress, and alloying effect. Direct band gap-modified Ge semiconductors with a high carrier mobility and radiation recombination efficiency can be applied to optoelectronic devices, which can improve the luminous efficiency dramatically, and they also have the potential application advantages in realizing monolithic optoelectronic integration (MOEI) and become a research hotspot in material fields. Among the various implementations of Ge band gap-type conversion, the related methods that are compatible with the Si process are most promising. It is such a method to etch around the Ge epitaxial layer on the Si substrate and introduce the biaxial tensile stress by SiGe selective filling. However, the influence of the width of the epitaxial layer, Ge composition, and Ge mesa region width on strain distribution and intensity is not clear yet. Accordingly, a finite element stress model of the selective epitaxy-induced direct band gap Ge scheme is established to obtain the material physical and geometric parameters of the Si1−xGex growth region. The result of finite element simulation indicates when the Si1−xGex epitaxial layer is 150–250 nm wide and the Ge composition is 0.3∼0.5, Ge mesa with 20–40 nm in width can be transformed into direct band gap semiconductors in the depth of 0–6 nm. The theoretical results can provide an important theoretical basis for the realization of subsequent related processes.

show abstract

First-principles Analysis of Indirect-to-Direct Band Gap Transition of Ge Under Tensile Strain

Cited by 2 publications

References 0 publications

Excitons under strain: light absorption and emission in strained hexagonal boron nitride

Excitons under strain: light absorption and emission in strained hexagonal boron nitride

Finite Element Stress Model of Direct Band Gap Ge Implementation Method Compatible with Si Process

Contact Info

Product

Resources

About