GaN as an Interfacial Passivation Layer: Tuning Band Offset and Removing Fermi Level Pinning for III–V MOS Devices

Zhang, Zhaofu; Cao, Ruyue; Wang, Changhong; Li, Hao Bo; Dong, Hong; Wang, Wei Hua; Lu, Feng; Cheng, Yahui; Xie, Xinjian; Liu, Hui; Cho, Kyeongjae; Wallace, Robert M.; Wang, Weichao

doi:10.1021/am507287f

Cited by 48 publications

(31 citation statements)

References 59 publications

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“…Suitable band edge discontinuities (i.e., band offsets) is a crucial requirement for the efficient operation of field-effect transistors [12,25]. The PDOS scheme can be used to roughly determine the band edge line-up in the interface supercell model [30,34]. Using this method, the energy difference between their valence band maxima (i.e., VBO) is roughly observed to be 1.3 eV, 1.4 eV, 0.7 eV and 0.4 eV for HfO 2 /VO 2 , ZrO 2 /VO 2 , Al 2 O 3 /VO 2 and TiO 2 /VO 2 interfaces in Fig.…”

Section: Resultsmentioning

confidence: 99%

Band alignment calculation of dielectric films on VO2

Zhang

Chen

Guo

et al. 2019

Microelectronic Engineering

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The chemical bonding and band edge line-up of several gate insulators on monoclinic (M1) phase VO 2 are studied based on hybrid density functional calculations. High dielectric constant HfO 2 and ZrO 2 , wide band gap oxide Al 2 O 3 , and narrower band gap TiO 2 are considered. The insulating interface supercells with a clean bandgap are built and adapted to analysis the band alignment. All the gate insulators show the type-I band alignment with VO 2. The valence band offset are all larger than 1 eV. The calculated conduction band offsets for HfO 2 , ZrO 2 and Al 2 O 3 are all larger than 2 eV. In terms of the band alignment, these three insulators can work as suitable gate dielectrics for VO 2-based device application, but more accurate line-up analysis on TiO 2 /VO 2 interface is still needed.

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Section: Resultsmentioning

confidence: 99%

Band alignment calculation of dielectric films on VO2

Zhang

Chen

Guo

et al. 2019

Microelectronic Engineering

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“…Negative E b means a stable heterostructure. The vacancy defect formation energy, which is important for predicting the concentration of certain defect, is defined as [34,35]:…”

Section: Computational Detailsmentioning

confidence: 99%

Tunable Electronic Properties of Graphene/g-AlN Heterostructure: The Effect of Vacancy and Strain Engineering

et al. 2019

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The structural and electronic properties of graphene/graphene-like Aluminum Nitrides monolayer (Gr/g-AlN) heterojunction with and without vacancies are systematically investigated by first-principles calculation. The results prove that Gr/g-AlN with nitrogen-vacancy (Gr/g-AlN-VN) is energy favorable with the smallest sublayer distance and binding energy. Gr/g-AlN-VN is nonmagnetic, like that in the pristine Gr/g-AlN structure, but it is different from the situation of g-AlN-VN, where a magnetic moment of 1 μB is observed. The metallic graphene acts as an electron acceptor in the Gr/g-AlN-VN and donor in Gr/g-AlN and Gr/g-AlN-VAl contacts. Schottky barrier height Φ B , n by traditional (hybrid) functional of Gr/g-AlN, Gr/g-AlN-VAl, and Gr/g-AlN-VN are calculated as 2.35 (3.69), 2.77 (3.23), and 1.10 (0.98) eV, respectively, showing that vacancies can effectively modulate the Schottky barrier height. Additionally, the biaxial strain engineering is conducted to modulate the heterojunction contact properties. The pristine Gr/g-AlN, which is a p-type Schottky contact under strain-free condition, would transform to an n-type contact when 10% compressive strain is applied. Ohmic contact is formed under a larger tensile strain. Furthermore, 7.5% tensile strain would tune the Gr/g-AlN-VN from n-type to p-type contact. These plentiful tunable natures would provide valuable guidance in fabricating nanoelectronics devices based on Gr/g-AlN heterojunctions.

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“…To correct the van der Waals interaction between the AlN and graphene sublayers, the DFT-D3 approach proposed by Grimme [ 38 ] was employed. A 20

vacuum thickness was constructed to cancel the interactions from the periodic images along the z-direction [ 39 , 40 ]. The

-centered Monkhorst–Pack [ 41 ] approach was used to sample the reciprocal space, and the grid density was set as 4 × 4 × 1.…”

Section: Computation Methodsmentioning

confidence: 99%

The External Electric Field-Induced Tunability of the Schottky Barrier Height in Graphene/AlN Interface: A Study by First-Principles

Liu

Zhang²,

Ding

et al. 2020

Nanomaterials

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Graphene-based van der Waals (vdW) heterojunction plays an important role in next-generation optoelectronics, nanoelectronics, and spintronics devices. The tunability of the Schottky barrier height (SBH) is beneficial for improving device performance, especially for the contact resistance. Herein, we investigated the electronic structure and interfacial characteristics of the graphene/AlN interface based on density functional theory. The results show that the intrinsic electronic properties of graphene changed slightly after contact. In contrast, the valence band maximum of AlN changed significantly due to the hybridization of Cp and Np orbital electrons. The Bader charge analysis showed that the electrons would transfer from AlN to graphene, implying that graphene would induce acceptor states. Additionally, the Schottky contact nature can be effectively tuned by the external electric field, and it will be tuned from the p-type into n-type once the electric field is larger than about 0.5 V/Å. Furthermore, the optical absorption of graphene/AlN is enhanced after contact. Our findings imply that the SBH is controllable, which is highly desirable in nano-electronic devices.

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GaN as an Interfacial Passivation Layer: Tuning Band Offset and Removing Fermi Level Pinning for III–V MOS Devices

Cited by 48 publications

References 59 publications

Band alignment calculation of dielectric films on VO2

Band alignment calculation of dielectric films on VO2

Tunable Electronic Properties of Graphene/g-AlN Heterostructure: The Effect of Vacancy and Strain Engineering

The External Electric Field-Induced Tunability of the Schottky Barrier Height in Graphene/AlN Interface: A Study by First-Principles

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