Electronic and Optical Properties of the Group-III Nitrides, their Heterostructures and Alloys

Lambrecht, Walter R. L.; Kim, Kwiseon; Rashkeev, Sergey N.; Segall, B.

doi:10.1557/proc-395-455

Cited by 22 publications

(4 citation statements)

References 39 publications

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“…In the case of InN, the spin-orbit coupling constants obtained in our pseudopotential calculations (∆ 2 = 3.9 meV and ∆ 3 = 5.5 meV) are only moderately smaller than spin-orbit splittings in AlN and GaN (see Table 1). It is in contrast to the recent all-electron calculations, which predict the value of the spin-orbit splitting ∆ 0 in the zincblende InN to be 3 meV [24] and 6 meV [25] (please note that in the cubic model of wurtzite structure ∆ 2 = ∆ 3 = ∆ 0 /3).…”

Section: Valence Band Parameters and Deformation Potentialscontrasting

confidence: 81%

Electronic structure of biaxially strained wurtzite crystals GaN, AlN, and InN

Majewski

Städele

Vogl

1996

MRS Internet j. nitride semicond. res.

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We present first-principles studies of the effect of biaxial (0001)-strain on the electronic structure of wurtzite GaN, AlN, and InN. We provide accurate predictions for the valence band splittings as a function of strain which greatly facilitates the interpretation of data from samples with unintentional growth-induced strain. The present calculations are based on the total-energy pseudopotential method within the local-density formalism and include the spin-orbit interaction nonperturbatively. For a given biaxial strain, all structural parameters are determined by minimization of the total energy with respect to the electronic and ionic degrees of freedom. Our calculations predict that the valence band state Γ9(Γ6) lies energetically above the Γ7(Γ1) states in GaN and InN, in contrast to the situation in AlN. In all three nitrides, we find that the ordering of these two levels becomes reversed for some value of biaxial strain. In GaN, this crossing takes place already at 0.32% tensile strain. For larger tensile strains, the top of the valence band becomes well separated from the lower states. The computed crystal-field and spin-orbit splittings in unstrained materials as well as the computed deformation potentials agree well with the available experimental data.

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Section: Valence Band Parameters and Deformation Potentialscontrasting

confidence: 81%

Electronic structure of biaxially strained wurtzite crystals GaN, AlN, and InN

Majewski

Städele

Vogl

1996

MRS Internet j. nitride semicond. res.

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“…The interaction between the N p and the occupied Ga d states results in a level repulsion, moving the valence-band maximum upwards. This p-d coupling tends to reduce the bandgaps as is known for nitride compounds [42,43]. The p-d coupling increases with small p-d energy differences and large overlap between the p-d orbitals.…”

Section: Electronic Band Structuresmentioning

confidence: 76%

“…In table 1 our results of structure optimization for zincblende AlN and GaN within LDA and GGA calculations are summarized and compared with some available experimental data [1,28,29] and recently published ab initio calculations [30][31][32][33][34][35][36][37][38][39][40]. We must note here that because of the unavailability of data on lattice constant for zinc-blende AlN, the experimental value mentioned in table 1 is deduced from the f Reference [43].…”

Section: Ground-state Propertiesmentioning

confidence: 99%

Zinc-blende AlN and GaN under pressure: structural, electronic, elastic and piezoelectric properties

Kanoun

Goumri‐Said

Merad

et al. 2004

Semicond. Sci. Technol.

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In this paper we report a theoretical study of the structural, elastic, electronic and piezoelectric properties of zinc-blende AlN and GaN under the pressure effect. The study is focused on the first-principles all electron full-potential augmented plane wave plus local orbitals calculations within the density-functional theory. The results of bulk properties, including lattice constants, bulk modulus and derivatives and band structures are obtained and compared using both the local density approximation (LDA) and the generalized gradient approximation (GGA) for the exchange-correlation functional. We find that the GGA does not give a significant improvement over LDA. We also report calculations for elastic constants as well as the internal-strained parameter and their behaviour under pressure. The electronic energy levels and ionicity factor are studied under hydrostatic pressure. We extend our investigation to the study of the stress effect on piezoelectric constants and transverse effective charges. Our results show that III-V nitrides resemble II-VI compounds in terms of the sign of the piezoelectric constants. The piezoelectric constants and transverse effective charges vary nonlinearly with pressure.

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“…The band structure of GaN has been calculated by several groups and the results have been well reviewed by Lambrecht and Segall (1994)-in figure 3 we show their summary of calculated band structures for both WZ and ZB GaN. In this paper we shall be concerned with the details only in the region of the fundamental energy gap, for other details the reader is referred to their paper.…”

Section: Electronic Propertiesmentioning

confidence: 99%

Group III nitride semiconductors for short wavelength light-emitting devices

1998

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The group III nitrides (AlN, GaN and InN) represent an important trio of semiconductors because of their direct band gaps which span the range 1.95-6.2 eV, including the whole of the visible region and extending well out into the ultraviolet (UV) range. They form a complete series of ternary alloys which, in principle, makes available any band gap within this range and the fact that they also generate efficient luminescence has been the main driving force for their recent technological development. High brightness visible light-emitting diodes (LEDs) are now commercially available, a development which has transformed the market for LED-based full colour displays and which has opened the way to many other applications, such as in traffic lights and efficient low voltage, flat panel white light sources. Continuously operating UV laser diodes have also been demonstrated in the laboratory, exciting tremendous interest for high-density optical storage systems, UV lithography and projection displays. In a remarkably short space of time, the nitrides have therefore caught up with and, in some ways, surpassed the wide band gap II-VI compounds (ZnCdSSe) as materials for short wavelength optoelectronic devices. The purpose of this paper is to review these developments and to provide essential background material in the form of the structural, electronic and optical properties of the nitrides, relevant to these applications. We have been guided by the fact that the devices so far available are based on the binary compound GaN (which is relatively well developed at the present time), together with the ternary alloys AlGaN and InGaN, containing modest amounts of Al or In. We therefore concentrate, to a considerable extent, on the properties of GaN, then introduce those of the alloys as appropriate, emphasizing their use in the formation of the heterostructures employed in devices. The nitrides crystallize preferentially in the hexagonal wurtzite structure and devices have so far been based on this material so the majority of our paper is concerned with it, however, the cubic, zinc blende form is known for all three compounds, and cubic GaN has been the subject of sufficient work to merit a brief account in its own right. There is significant interest based on possible technological advantages, such as easier doping, easier cleaving (for laser facets) and easier contacting.

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Electronic and Optical Properties of the Group-III Nitrides, their Heterostructures and Alloys

Cited by 22 publications

References 39 publications

Electronic structure of biaxially strained wurtzite crystals GaN, AlN, and InN

Electronic structure of biaxially strained wurtzite crystals GaN, AlN, and InN

Zinc-blende AlN and GaN under pressure: structural, electronic, elastic and piezoelectric properties

Group III nitride semiconductors for short wavelength light-emitting devices

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