Stacking and electric field effects in atomically thin layers of GaN

Xu, Dongwei; He, Haiying; Pandey, Ravindra; Karna, Shashi P.

doi:10.1088/0953-8984/25/34/345302

Cited by 86 publications

(78 citation statements)

References 50 publications

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“…The average interlayer interaction energy is 200 meV. The cohesive energies calculated for b-and t-GaN are in agreement with those of Xu et al [61]. The extension of b-and t-GaN is the formation of multilayer m-GaN or 3D layered p-GaN, which is periodic in the direction perpendicular to the atomic planes.…”

Section: Gan Bilayer and Multilayer Structuressupporting

confidence: 87%

GaN: From three- to two-dimensional single-layer crystal and its multilayer van der Waals solids

et al. 2016

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Three-dimensional (3D) GaN is a III-V compound semiconductor with potential optoelectronic applications. In this paper, starting from 3D GaN in wurtzite and zinc-blende structures, we investigated the mechanical, electronic, and optical properties of the 2D single-layer honeycomb structure of GaN (g-GaN) and its bilayer, trilayer, and multilayer van der Waals solids using density-functional theory. Based on high-temperature ab initio molecular-dynamics calculations, we first showed that g-GaN can remain stable at high temperature. Then we performed a comparative study to reveal how the physical properties vary with dimensionality. While 3D GaN is a direct-band-gap semiconductor, g-GaN in two dimensions has a relatively wider indirect band gap. Moreover, 2D g-GaN displays a higher Poisson ratio and slightly less charge transfer from cation to anion. In two dimensions, the optical-absorption spectra of 3D crystalline phases are modified dramatically, and their absorption onset energy is blueshifted. We also showed that the physical properties predicted for freestanding g-GaN are preserved when g-GaN is grown on metallic as well as semiconducting substrates. In particular, 3D layered blue phosphorus, being nearly lattice-matched to g-GaN, is found to be an excellent substrate for growing g-GaN. Bilayer, trilayer, and van der Waals crystals can be constructed by a special stacking sequence of g-GaN, and they can display electronic and optical properties that can be controlled by the number of g-GaN layers. In particular, their fundamental band gap decreases and changes from indirect to direct with an increasing number of g-GaN layers.

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Section: Gan Bilayer and Multilayer Structuressupporting

confidence: 87%

GaN: From three- to two-dimensional single-layer crystal and its multilayer van der Waals solids

et al. 2016

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“…= 51.36 V Å À1 ) along the perpendicular direction is applied, no evident effect on the band structure of the single-layer BP is observed. For a bilayer, there are five possible stacking conformations, 25 namely, AA-, AAI-, AB-, ABI-, and ABII-stacking (more details in the ESI †), respectively. On the basis of E total and bandgap, AB-stacking is the most favorable configuration among the five possible stacking structures, whereas AA-stacking is the most undesirable one.…”

Section: Resultsmentioning

confidence: 99%

Effect of multilayer structure, stacking order and external electric field on the electrical properties of few-layer boron-phosphide

Chen

Tan

Yang

et al. 2016

Phys. Chem. Chem. Phys.

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Development of nanoelectronics requires two-dimensional (2D) systems with both direct-bandgap and tunable electronic properties as they act in response to the external electric field (E-field). Here, we present a detailed theoretical investigation to predict the effect of atomic structure, stacking order and external electric field on the electrical properties of few-layer boron-phosphide (BP). We demonstrate that the splitting of bands and bandgap of BP depends on the number of layers and the stacking order. The values for the bandgap show a monotonically decreasing relationship with increasing layer number. We also show that AB-stacking BP has a direct-bandgap, while ABA-stacking BP has an indirect-bandgap when the number of layers n > 2. In addition, for a bilayer and a trilayer, the bandgap increases (decreases) as the electric field increases along the positive direction of the external electric field (E-field) (negative direction). In the case of four-layer BP, the bandgap exhibits a nonlinearly decreasing behavior as the increase in the electric field is independent of the electric field direction. The tunable mechanism of the bandgap can be attributed to a giant Stark effect. Interestingly, the investigation also shows that a semiconductor-to-metal transition may occur for the four-layer case or more layers beyond the critical electric field. Our findings may inspire more efforts in fabricating new nanoelectronics devices based on few-layer BP.

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“…2. [24][25][26][27] To analyze the unique changes of the band gap characters in monolayer Sc 2 CO 2 , variations of the energy gaps between the K and G points of the lowest conduction band and the topmost valence band by the external E-field are presented in Fig. In addition, the original band gap, which is the K (conduction band minimum, CBM) to G (valence band maximum, VBM) indirect band gap of 1.830 eV, is also little affected under a negative and small positive E-field.…”

Section: Resultsmentioning

confidence: 99%

“…3,[19][20][21][22][23][24] Generally, band gap tuning by an external E-field has been used in multilayer systems such as bilayer graphene or transition-metal dichalcogenide, and a multilayer BN-graphene heterostructure. 3,[19][20][21][22][23][24] Generally, band gap tuning by an external E-field has been used in multilayer systems such as bilayer graphene or transition-metal dichalcogenide, and a multilayer BN-graphene heterostructure.…”

Section: Introductionmentioning

confidence: 99%

Achieving a direct band gap in oxygen functionalized-monolayer scandium carbide by applying an electric field

Lee

Hwang

Cho

et al. 2014

Phys. Chem. Chem. Phys.

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In the present paper, the band gap characteristics of oxygen functionalized-monolayer scandium carbide (monolayer Sc2CO2) under a perpendicular external electric field (E-field) were studied using DFT calculations for the potential application of MXene in optoelectronic and optical nanodevices. In contrast to general pristine single-layer materials under an external E-field, monolayer Sc2CO2 undergoes an indirect to direct band gap transition under a positive E-field, and the band gap value changes sharply after the band gap transition. Remarkable variations of the band gap properties are induced by the distinct sensitivity between the Γ and K points in the lowest conduction band to the perpendicular E-field, and different types of orbital lead to the dissimilar response of each point. The present work clearly suggests an effective direction to obtain attractive band gap properties in monolayer MXene using an external E-field for next generation optoelectronic and optical devices.

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Stacking and electric field effects in atomically thin layers of GaN

Cited by 86 publications

References 50 publications

GaN: From three- to two-dimensional single-layer crystal and its multilayer van der Waals solids

GaN: From three- to two-dimensional single-layer crystal and its multilayer van der Waals solids

Effect of multilayer structure, stacking order and external electric field on the electrical properties of few-layer boron-phosphide

Achieving a direct band gap in oxygen functionalized-monolayer scandium carbide by applying an electric field

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