Bipolar self-doping in ultra-wide bandgap spinel ZnGa2O4

Chi, Zeyu; Tarntair, Fu-Gow; Frégnaux, Mathieu; Wu, Wan-Yu; Sartel, Corinne; Madaci, Ismail; Chapon, Patrick; Sallet, Vincent; Dumont, Y.; Pérez‐Tomás, Amador; Horng, Ray−Hua; Chikoidze, Ekaterine

doi:10.1016/j.mtphys.2021.100466

Cited by 30 publications

(24 citation statements)

References 71 publications

(98 reference statements)

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“…The spinel’s off-stoichiometry, from the ideal 1:2:4 proportions, or the creation of cation antisite defects are known routes for doping these compounds. Dominant defects in spinels are antisite donors (e.g., Zn Ga ) or donor-like Ga 3+ (O h )-on-T d and antisite acceptors (e.g., GaZn) with acceptor-like Zn 2+ (T d )-on-O h antisite defects resulting in an intrinsic bipolar power semiconductor [ 190 ]. ZnGa 2 O 4 is therefore a potential outstanding UWBG (~5 eV) oxide semiconductor but is only one among the many possible spinel oxides.…”

Section: Other Emerging Oxide Semiconductors For Power Electronicsmentioning

confidence: 99%

Ga2O3 and Related Ultra-Wide Bandgap Power Semiconductor Oxides: New Energy Electronics Solutions for CO2 Emission Mitigation

et al. 2022

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Currently, a significant portion (~50%) of global warming emissions, such as CO2, are related to energy production and transportation. As most energy usage will be electrical (as well as transportation), the efficient management of electrical power is thus central to achieve the XXI century climatic goals. Ultra-wide bandgap (UWBG) semiconductors are at the very frontier of electronics for energy management or energy electronics. A new generation of UWBG semiconductors will open new territories for higher power rated power electronics and solar-blind deeper ultraviolet optoelectronics. Gallium oxide—Ga2O3 (4.5–4.9 eV), has recently emerged pushing the limits set by more conventional WBG (~3 eV) materials, such as SiC and GaN, as well as for transparent conducting oxides (TCO), such asIn2O3, ZnO and SnO2, to name a few. Indeed, Ga2O3 as the first oxide used as a semiconductor for power electronics, has sparked an interest in oxide semiconductors to be investigated (oxides represent the largest family of UWBG). Among these new power electronic materials, AlxGa1-xO3 may provide high-power heterostructure electronic and photonic devices at bandgaps far beyond all materials available today (~8 eV) or ZnGa2O4 (~5 eV), enabling spinel bipolar energy electronics for the first time ever. Here, we review the state-of-the-art and prospects of some ultra-wide bandgap oxide semiconductor arising technologies as promising innovative material solutions towards a sustainable zero emission society.

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Section: Other Emerging Oxide Semiconductors For Power Electronicsmentioning

confidence: 99%

Ga2O3 and Related Ultra-Wide Bandgap Power Semiconductor Oxides: New Energy Electronics Solutions for CO2 Emission Mitigation

et al. 2022

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“…Ultra-wide band gap semiconductors (WBS) have attracted great attention in recent years for their application in high-power transistors for energy conversion and solar-blind UV detectors, combining high critical electric field strength, transparency in the visible spectrum, and high conductivity through doping [1][2][3][4][5]. Among the promising semiconductor materials, Ga 2 O 3 stands out with band gap in the range of 4.6-5.0 eV and a large electric breakdown field, resulting in Baliga's figure of merit (BFOM) just smaller than diamond and with capability that goes beyond existent technologies based on SiC and GaN [1,6].…”

Section: Introductionmentioning

confidence: 99%

“…Recent studies have focused on ZnGa 2 O 4 as a ultrawide band gap semiconductor for devices [2][3][4][5]. With a band gap of 5.0 eV, room-temperature electron mobility of 10 2 cm 2 /V.s, and high dielectric constant of 10.4, ZnGa 2 O 4 has been considered as an alternative or, at least, as a complement to Ga 2 O 3 [3][4][5]. Thin films of spinel ZnGa 2 O 4 have been grown epitaxially on sapphire substrate [5].…”

Section: Introductionmentioning

confidence: 99%

“…With a band gap of 5.0 eV, room-temperature electron mobility of 10 2 cm 2 /V.s, and high dielectric constant of 10.4, ZnGa 2 O 4 has been considered as an alternative or, at least, as a complement to Ga 2 O 3 [3][4][5]. Thin films of spinel ZnGa 2 O 4 have been grown epitaxially on sapphire substrate [5]. Considering an average in all directions, experimental results indicate that the thermal dissipation in ZnGa 2 O 4 thin films is about 10% more efficient than in Ga 2 O 3 [3,8].…”

Section: Introductionmentioning

confidence: 99%

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Hole conductivity through a defect band in $\rm ZnGa_2O_4$

Sabino¹,

Chatratin²,

Janotti³

et al. 2022

Preprint

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Semiconductors with wide band gap (> 3.0 eV), high dielectric constant (> 10), good thermal dissipation, and capable of n and p-type doping are highly desirable for high-energy power electronic devices. Recent studies indicate that ZnGa 2 O 4 may be suitable for these applications, standing out as an alternative to Ga 2 O 3 . The simple face centered cubic spinel structure of ZnGa 2 O 4 results in isotropic electronic and optical properties, in contrast to the large anisotropic properties of the β-monoclinic Ga 2 O 3 . In addition, ZnGa 2 O 4 has shown, on average, better thermal dissipation and potential for n-and p-type conductivity. Here we use density functional theory and hybrid functional calculations to investigate the electronic, optical, and point defect properties of ZnGa 2 O 4 , focusing on the possibility for p-and n-type conductivity. We find that the cation antisite GaZn is the lowest energy donor defect that can lead to unintentional n-type conductivity. The stability of self-trapped holes (small hole polarons) and the high formation energy of acceptor defects make it difficult to achieve p-type conductivity. However, with excess of Zn, forming Zn (1+2x) Ga 2(1-x) O 4 alloys display an intermediate valence band, facilitating p-type conductivity. Due to the localized nature of this intermediate valence band, p-type conductivity by polaron hopping is expected, explaining the low mobility and low hole density observed in recent experiments.

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“…Recently, Chi et al and Chikoidze et al demonstrated the p-type ZnGa 2 O 4 semiconductor (5 eV), which could pave the way for bipolar oxide energy electronics by reducing switching and conversion losses. This is due to ZnGa 2 O 4 s combination of the required qualities for sustaining large electrical fields in p-n junctions in the off-state, together with low losses in the on-state [12,13]. ZnGa 2 O 4 possesses the cubic symmetric spinel structure with the space group of Fd3m, where Zn 2+ cations occupy tetrahedral sites and Ga 3+ cations occupy octahedral sites with oxygen atoms in close-packed cubic structures [11,14].…”

Section: Introductionmentioning

confidence: 99%

The Effect of Annealing Ambience on the Material and Photodetector Characteristics of Sputtered ZnGa2O4 Films

et al. 2021

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Spinel ZnGa2O4 films were grown on c-plane sapphire substrates at the substrate temperature of 400 °C by radio-frequency magnetron sputtering. Post thermal annealing was employed at the annealing temperature of 700 °C in order to enhance their crystal quality. The effect of thermal annealing on the microstructural and optoelectronic properties of ZnGa2O4 films was systematically investigated in various ambiences, such as air, nitrogen, and oxygen. The X-ray diffraction patterns of annealed ZnGa2O4 films showed the crystalline structure to have (111) crystallographic planes. Transmission electron micrographs verified that ZnGa2O4 film annealed under air ambience possesses a quasi-single-crystalline structure. This ZnGa2O4 film annealed under air ambience exhibited a smooth surface, an excellent average transmittance above 82% in the visible region, and a wide bandgap of 5.05 eV. The oxygen vacancies under different annealing ambiences were revealed a substantial impact on the material and photodetector characteristics by X-ray photoelectron spectrum investigations. ZnGa2O4 film exhibits optimal performance as a metal-semiconductor-metal photodetector when annealed under air ambience. Under these conditions, ZnGa2O4 film exhibits a higher photo/dark current ratio of ~104 order, as well as a high responsivity of 2.53 A/W at the bias of 5 V under an incident optical light of 240 nm. These results demonstrate that quasi-single-crystalline ZnGa2O4 films have significant potential in deep-ultraviolet applications.

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Bipolar self-doping in ultra-wide bandgap spinel ZnGa2O4

Cited by 30 publications

References 71 publications

Ga2O3 and Related Ultra-Wide Bandgap Power Semiconductor Oxides: New Energy Electronics Solutions for CO2 Emission Mitigation

Ga2O3 and Related Ultra-Wide Bandgap Power Semiconductor Oxides: New Energy Electronics Solutions for CO2 Emission Mitigation

Hole conductivity through a defect band in $\rm ZnGa_2O_4$

The Effect of Annealing Ambience on the Material and Photodetector Characteristics of Sputtered ZnGa2O4 Films

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