Intrinsic acceptor antisite defects in GaAs under hydrostatic pressure

Kangarlu, A.; Guarriello, H.; Berney, R.; Yu, P. W.

doi:10.1063/1.106046

Cited by 10 publications

(6 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…15 and 16͒ spectra in diamond-anvil cells. Due to the technological importance of GaAs, the DIT was used to investigate various aspects of band-structure theory including the scattering cross sections of intraband transitions, 1,2 the formation of shallow impurities, [17][18][19] the nature and origin of the DX center, [20][21][22] and the dynamics of excited carriers. 23,24 Application of hydrostatic pressure to a cubic crystal causes the volume to decrease while preserving the crystal symmetry.…”

mentioning

confidence: 99%

Transformation of GaAs into an indirectL-band-gap semiconductor under uniaxial strain

2009

View full text Add to dashboard Cite

We report the direct-to-indirect band-gap transition in GaAs under nonhydrostatic compression. Uniaxial strain was produced in GaAs single crystals by impact loading along the ͓100͔ and ͓111͔ orientations up to longitudinal stresses of 5.5 GPa. Band-gap shifts were determined from low-temperature photoluminescence measurements from Te-and Zn-doped samples. For strain along the ͓100͔ direction, GaAs undergoes a ⌫-X band transition similar to what occurs under hydrostatic pressure. Strain along ͓111͔, in contrast, produces a large splitting of the L band. This causes the L-band minimum to plunge downward and transform GaAs into an indirect L-band-gap semiconductor.The effect of strains on the band structure of semiconductors is of fundamental interest in condensed-matter physics. Intervalley scattering processes involving electronic transitions between different conduction-band ͑CB͒ minima depend strongly on the deformation potentials. 1,2 In strained semiconductors, band-gap distortions affect carrier transport and recombination processes. 3,4 Strain effects are particularly important as dimensions approach the nanoscale; strains can reach 3% in quantum-well heterostructures 5 and up to 7% in quantum dots, 6 resulting in significant changes in the optical properties.Semiconductors with the diamond or zinc-blende crystal structure have CB minima located at the ͓000͔ ͑⌫͒, ͓100͔ ͑X͒, and ͓111͔ ͑L͒ symmetry points of the Brillouin zone. 7 Under hydrostatic pressure, the CB minima at the ⌫ and L points shift upward in energy, with the shift being larger for the ⌫ band while the X-band minimum shifts downward. 8 These shifts alter the band gap of each semiconductor in a unique way. Si shows a constant reduction in the indirect X band gap with applied pressure. 9 In Ge, an initial gradual increase in the indirect L band gap intersects the decreasing indirect X band gap at 3.5 GPa. 10 Most III-V compound semiconductors have a direct ⌫ band gap at ambient conditions. Under hydrostatic pressure, the upward shift of the ⌫ band eventually intersects the X band and the material undergoes a direct-to-indirect transition ͑DIT͒. 11,12 In GaAs, the DIT was observed at ϳ4 GPa by measuring absorption 13,14 and photoluminescence ͑PL͒ ͑Refs. 15 and 16͒ spectra in diamond-anvil cells. Due to the technological importance of GaAs, the DIT was used to investigate various aspects of band-structure theory including the scattering cross sections of intraband transitions, 1,2 the formation of shallow impurities, 17-19 the nature and origin of the DX center, 20-22 and the dynamics of excited carriers. 23,24 Application of hydrostatic pressure to a cubic crystal causes the volume to decrease while preserving the crystal symmetry. In contrast, an arbitrary strain tensor, e ij , can always be decomposed into a spherical part ͑volumetric strains͒ and a deviatoric part ͑shear strains͒. The deviatoric strains alter the symmetry and lift the degeneracy of electronic states. The role of deviatoric strains can be studied by applying uniaxial stress loa...

show abstract

mentioning

confidence: 99%

Transformation of GaAs into an indirectL-band-gap semiconductor under uniaxial strain

2009

View full text Add to dashboard Cite

show abstract

“…The data reported by Yu and Welber (~3 GPa) 103 is considerably smaller than this value. Kangarlu et al 110 have also reported the L 6 C -X 6 C crossover at 2.5 -3.0 GPa from the photoluminescence spectra measured under hydrostatic pressure. Our estimated L 6 C -X 6 C crossover pressure (-2.8 GPa) is in good agreement with this result (see Fig.…”

Section: Pressurementioning

confidence: 91%

“…The spin-orbit splitoff hole band (r 7 v ) is twofold spin degenerate at point T, and it splits as |k| 3 to lowest order in all but the [111] and [100] directions where it remains degenerate. The s-like T 6 C conduction band also splits as |k| 3 for k in die [110] direction.…”

Section: K(w) W(w) Uamentioning

confidence: 99%

“…137 studied theoretically in detail by a number of groups (GaAs, 110 AlAs, 7 " 9 "' 14 and Al,Ga,. x As alloy 15 ).…”

mentioning

confidence: 99%

“…7.3). The Ej transitions are expected to take along the [110] (I) or near X. The lowest indirect absorption edge in GaAs corresponds to transitions from the highest valence band at the T point to the lowest conduction band at the L(X) point [i.e., E g L OV^L/) and E g x flY^X/)].…”

mentioning

confidence: 99%

See 2 more Smart Citations

Energy-Band Structure: Energy-Band Gaps of Bulk Materials

Adachi¹

1994

GaAs and Related Materials

View full text Add to dashboard Cite

The wave function TCr) of the electrons in the crystal lattice is expressed by the well-known Bloch's theorem:where the function U k (r) has the period of the crystal lattice such mat U k (r)=U k (r+T) (here T is any vector of the Bravais lattice). The nearly free-electron approximation is a good standing point for discussing the energy band theory. It explains the origin of the band gap and that of the effective mass m* which is defined as the reciprocal of the curvature of E (energy) versus k (wavevector) diagram. The functional dependence of E on k for the various bands, E"(k), is defined by the Schrodinger equation:HT(r) = _EL + V(r) = E^r) (7.2) 2m* where p 2 /2m* is the kinetic energy (p=-ihV), V(r) is the potential energy, and E is the energy eigenvalue. Since the electrons in the crystal are influenced by the periodic potential, the electron mass m* used in Eq. (7.2) differs largely from the free electron mass m<, (see Chapter 8).The reciprocal space, also called phase space, k-space, and momentum space, is a convenient tool to describe the behavior of both vibrational states and electronic states. The coordinate axes of the reciprocal lattice are the wavevectors of the plane waves corresponding to the vibrational modes (Section 5.

show abstract

Gallium arsenide (GaAs), direct energy gap

Landolt-Börnstein - Group III Condensed Matter

View full text Add to dashboard Cite

Intrinsic acceptor antisite defects in GaAs under hydrostatic pressure

Cited by 10 publications

References 19 publications

Transformation of GaAs into an indirectL-band-gap semiconductor under uniaxial strain

Transformation of GaAs into an indirectL-band-gap semiconductor under uniaxial strain

Energy-Band Structure: Energy-Band Gaps of Bulk Materials

Gallium arsenide (GaAs), direct energy gap

Contact Info

Product

Resources

About