Computational discovery of p-type transparent oxide semiconductors using hydrogen descriptor

Yim, Kanghoon; Youn, Yong; Lee, Miso; Yoo, Do-Sik; Lee, Joohee; Cho, Sung Haeng; Han, Seungwu

doi:10.1038/s41524-018-0073-z

Cited by 74 publications

(83 citation statements)

References 41 publications

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“…In contrast, previous first-principles studies on the p-type dopability of β-Ga 2 O 3 have revealed a lack of shallow acceptors [15,16] and formation of self-trapped holes (STHs) [17][18][19], both of which hinder efficient p-type doping. Apart from exceptions including Cu (I) and Sn (II) oxides, the upper valence bands of oxides are mainly composed of O 2p orbitals and have small energy dispersions compared with other compounds such as nitrides, phosphides, and arsenides [20][21][22][23][24][25][26]. The relatively localized valence states could lead to STH formation and, therefore, low-hole mobility [17].…”

Section: Introductionmentioning

confidence: 99%

First-principles study of self-trapped holes and acceptor impurities in Ga2O3 polymorphs

Gake

Kumagai

Oba

2019

Phys. Rev. Materials

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We investigate the stability of self-trapped holes (STHs) and the acceptor levels of substitutional Mg and N impurities in α-, β-, δ-, and ε-Ga 2 O 3 using first-principles calculations based on the hybrid functional approach to assess their p-type dopability. When Fock-exchange and screening parameter values in the Heyd-Scuseria-Ernzerhof (HSE) hybrid functional are optimized to satisfy the generalized Koopmans' theorem for a STH level in β-Ga 2 O 3 , the band gap is slightly overestimated, while functionals that well reproduce the band gap show slight convex behavior against the fractional electron number. However, the absolute position of the STH level at a fixed geometry is nearly independent of the parameter value, showing that the results are robust as long as the STH geometry and localized electronic nature are appropriately described and the band edges are well reproduced. In all of the polymorphs, holes localize with high self-trapping energies rather than being delocalized. Furthermore, both Mg and N impurities introduce polaronic acceptor states, and their acceptor levels lie far above the valence band maximum in all the polymorphs. Thus, the p-type doping of the four Ga 2 O 3 polymorphs seems unfeasible in terms of the STH formation and the related deep, polaronic acceptor nature of the Mg and N impurities.

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Section: Introductionmentioning

confidence: 99%

First-principles study of self-trapped holes and acceptor impurities in Ga2O3 polymorphs

Gake

Kumagai

Oba

2019

Phys. Rev. Materials

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“…4,5,6 This discovery shifted the research interest from intrinsic defects to reactive impurities and their impact on the defect stability and materials properties in general. 4,7,8 Owing to the fully occupied orbitals, it is intuitively thought that noble gases remain inert during the interaction with various materials. Therefore, it is a common belief that the presence of a noble gas (e.g., Ar) during sputtering or wet-chemical synthesis inside a glove box does not affect properties of the product material.…”

Section: Introductionmentioning

confidence: 99%

Noble gas as a functional dopant in ZnO

2019

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Owing to fully occupied orbitals, noble gases are considered to be chemically inert and to have limited effect on materials properties under standard conditions. However, using first-principles calculations, we demonstrate herein that the insertion of noble gas (i.e., He, Ne, or Ar) in ZnO results in local destabilization of electron density of the material driven by minimization of an unfavorable overlap of atomic orbitals of the noble gas and its surrounding atoms. Specifically, the noble gas defect (interstitial or substitutional) in ZnO pushes the electron density of its surrounding atoms away from the defect. Simultaneously, the host material confines the electron density of the noble gas. As a consequence, the interaction of He, Ne, or Ar with O vacancies of ZnO in different charge states q (ZnO:VO q ) affects the vacancy stability and their electronic structures. Remarkably, we find that the noble gas is a functional dopant that can delocalize the deep in-gap VO q states and lift electrons associated with the vacancy to the conduction band.

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“…Moreover, though n‐type WBGSs (e.g., ZnO, Ga 2 O 3 , and AlGaN) with good conductivity and stability can operate in the UV and DUV range (280−390 nm), it is not possible to convert them to a p‐type material with good stability and conductivity due to their intrinsic electronic properties . Consequently, no highly stable conductive p‐type DUV WBGS operating in both UV‐B and UV‐C region presently exists …”

mentioning

confidence: 99%

Novel P‐Type Wide Bandgap Manganese Oxide Quantum Dots Operating at Deep UV Range for Optoelectronic Devices

Mitra

Pak

Alaal

et al. 2019

Advanced Optical Materials

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in a wide range of industrial applications, such as homeland security, medical diagnostics, food curing, sanitation, chemical and biological threat detection, space-tospace communications, missile detection, military surveillance, target detection and acquisition, transparent thin-film transistors, solar cells, white lighting, sterilization, medical treatment, and touch display panels. [1][2][3][4][5][6][7] For example, the most commercial DUV photodetectors are produced using UV-enhanced narrow bandgap semiconductors, mainly Si-based photodetector. [8,9] However, the narrow bandgap materials are ineffective in rejecting signals in the UV−vis−IR spectral region, making them unsuitable for DUV applications. Thus, high-quality DUV WBGSs are still needed to produce high-performance DUV optoelectronic devices. In each of the aforementioned fields, scientists and industry practitioners are looking to overcome different challenges. There is a growing demand for both p-type and n-type WBGSs that possess good stability and conductivity. The main obstacle to the achievement of this goal stems from the lack of p-type wide bandgap materials operating in the DUV range below 300 nm (i.e., >4.1 eV) that exhibit good p-type stability. Currently, the p-type materials having bandgap in the UV-A range (such as p-type GaN, Cu 2 O, and SnO) are utilized in DUV optoelectronics, which severely downgrade device performance, as their bandgaps are limited to the UV-A-to-visible spectral region (320-400 nm). [10,11] Moreover, though n-type WBGSs (e.g., ZnO, Ga 2 O 3 , and AlGaN) with good conductivity and stability can operate in the UV and DUV range (280−390 nm), it is not possible to convert them to a p-type material with good stability and conductivity due to their intrinsic electronic properties. [2,6,[11][12][13][14][15][16] Consequently, no highly stable conductive p-type DUV WBGS operating in both UV-B and UV-C region presently exists. [17] Further advances in the field of DUV optoelectronics are hindered by other issues, such as the difficulty in developing new cost-effective material production and fabrication methods that could replace the expensive and high vacuum-based technologies presently in use. Thus, as DUV-WBGS based devices tend Wide bandgap semiconductor (WBGS)-based deep UV (DUV) devices lag behind those operating in the visible and IR range, as no stable p-type WBGS that operates in the DUV region (<300 nm) presently exists. Here, solutionprocessed p-type manganese oxide WBGS quantum dots (MnO QDs) are explored. Highly crystalline MnO QDs are synthesized via femtosecond-laser ablation in liquid. The p-type nature of these QDs is demonstrated by Kelvin probe and field effect transistor measurements, along with density functional theory calculations. As proof of concept, a high-performance, self-powered, and solar-blind Schottky DUV photodetector based on such QDs is fabricated, which is capable of detecting under ambient conditions. The carrier collection efficiency is enhanced by asymmetric electrode structure, leadi...

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Computational discovery of p-type transparent oxide semiconductors using hydrogen descriptor

Cited by 74 publications

References 41 publications

First-principles study of self-trapped holes and acceptor impurities in Ga2O3 polymorphs

First-principles study of self-trapped holes and acceptor impurities in Ga2O3 polymorphs

Noble gas as a functional dopant in ZnO

Novel P‐Type Wide Bandgap Manganese Oxide Quantum Dots Operating at Deep UV Range for Optoelectronic Devices

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