Extending the metal-induced gap state model of Schottky barriers

Robertson, John; Guo, Yuzheng; Zhang, Zhaofu; Li, Hongfei

doi:10.1116/6.0000164

Cited by 16 publications

(9 citation statements)

References 47 publications

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“…Some exceptions to the MIGS model were found for semiconductors interfaces with metals which contain an underlying covalent lattice such as silicides. These interfaces apparently have weaker pinning, but actually have extra gap states which cause their SBHs to depend quite strongly on silicide work function [19,20].…”

Section: Introductionmentioning

confidence: 99%

Schottky barrier heights of defect-free metal/ZnO, CdO, MgO, and SrO interfaces

Chen

Zhang

Guo

et al. 2021

Journal of Applied Physics

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The Schottky barrier heights (SBHs) of defect-free interfaces of ZnO, CdO, MgO and SrO with various metals and different terminations are investigated by density functional supercell calculations. The oxide bands are corrected for their density functional band gap error by applying U-type treatment to their metal-d and O-p states where necessary. The p-type SBHs are found to decrease linearly with increasing metal work function. The pinning factor S of the non-polar and polar interfaces are similar for each oxide. S is found to be 0.26, 0.56, 0.74 and 0.96 for CdO, ZnO, MgO and SrO, respectively, with S increasing for increased oxide ionicity. The calculated pinning factors are generally consistent with the metal-induced gap states (MIGS) model in terms of variation with ionicity and dielectric constant. A significant shift of SBHs from the non-polar to the polar interfaces of 0.4 eV, 1 eV and 0.5 eV for ZnO, MgO and SrO, respectively, can be explained by an interfacial dipole. Our results are also useful to describe Co,Fe|MgO interfaces in magnetic tunnel junctions.

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Section: Introductionmentioning

confidence: 99%

Schottky barrier heights of defect-free metal/ZnO, CdO, MgO, and SrO interfaces

Chen

Zhang

Guo

et al. 2021

Journal of Applied Physics

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“…The Schottky barrier height (SBH) plays a vital role in the metal/semiconductor interfacial system or Schottky-based devices. In the theory of the Schottky–Mott model [ 50 , 51 ], the n-type and p-type Schottky barrier are represented by

separately, where

is the n-type SBH;

is the p-type SBH; and

is the Fermi level, which is referred to as zero during the study. Without an external electric field, the

and

of graphene/AlN were found to be 2.3 eV and 0.8 eV, respectively.…”

Section: Resultsmentioning

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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“…However, the nanoparticle e-bean p-Si/Pt EB (NP) sample displayed a fixed E oc independent of E (A/A – ) indicative of a buried junction. The buried junction in the p-Si/Pt EB (NP) likely arises due to Fermi level pinning caused by metal-induced states in the Si. − The smaller E oc of the p-Si/Pt el (NP) electrodes compared to p-Si-H electrodes was likely due to attenuation of the light by the Pt particles on the Si surface. The E oc for p-Si/Pt el (NP) electrodes was consistent with the performance of the electrodes in light-driven HER. − ,,, …”

Section: Discussionmentioning

confidence: 99%

Origin of the Electrical Barrier in Electrolessly Deposited Platinum Nanoparticles on p-Si Surfaces

Nunez

Cabán-Acevedo

et al. 2021

J. Phys. Chem. C

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Pt deposited by either sputtering or electron-beam (e-beam) evaporation on p-Si forms an ohmic contact, with zero photovoltage and very little photogenerated charge-carrier collection. However, electro-or electroless deposition of Pt onto p-Si produces a rectifying junction that generates a photovoltage of ∼300 mV under simulated 1 sun illumination. To explain these differences, we have characterized junctions formed by electroless or e-beam deposition of Pt onto H-terminated or oxide-coated p-Si substrates using impedance spectroscopy, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and electrochemical current density vs potential (J−E) characteristics. When Pt was deposited electrolessly, XPS and TEM measurements revealed a thin interfacial SiO x layer of 1−6 nm thickness under the Pt overlayer. Moreover, open-circuit potential measurements under illumination on electrolessly deposited Pt on a p-Si electrode showed that the junction was a function of the Nernstian potential of the contacting electrolyte solution. Creating an analogous junction by e-beam deposition of Pt required oxidation of the Si surface prior to Pt deposition, followed by etching in HF to remove oxide on the exposed Si surface. The resulting structure has both an interfacial SiO x layer under the Pt and a H-terminated Si surface on the bare areas. Additionally, under a H 2 atmosphere, Pt can adsorb hydrogen that can diffuse to the SiO x /Pt interface and produce a dipole layer. This information allowed formulation of a model for the charge transfer across p-Si/SiO x /Pt interfaces. When in contact with a solution having a kinetically facile redox couple, the current is carried across the Si/electrolyte interface, and the electrode has the properties of a semiconductor/liquid junction. In contrast, when in contact with a solution with a large kinetic barrier to interfacial charge transfer, such as the hydrogen evolution reaction, the current instead passes predominantly through the SiO x layer to the Pt and then reacts with protons in the solution. In this situation, the junction to the semiconductor is buried and occurs at the Si/SiO x /Pt interface. The Si/SiO x /Pt contact displays an increase in barrier height due to the hydrogen-induced dipoles. Consequently, the barrier height for an electrode made by electroless deposition of Pt onto Si is determined by the pathway that the electrons traverse to reach the solution.

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Extending the metal-induced gap state model of Schottky barriers

Cited by 16 publications

References 47 publications

Schottky barrier heights of defect-free metal/ZnO, CdO, MgO, and SrO interfaces

Schottky barrier heights of defect-free metal/ZnO, CdO, MgO, and SrO interfaces

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

Origin of the Electrical Barrier in Electrolessly Deposited Platinum Nanoparticles on p-Si Surfaces

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