- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Gallium Oxide || Growth, properties, and applications of β-Ga2O3 nanostructures
摘要： This chapter provided a brief overview for β-Ga2O3 nanostructures from a growth aspect to device applications. The outstanding properties of β-Ga2O3 such as large bandgap, high breakdown field, thermal and chemical stability, along with advantageous properties due to its nanostructures morphology such as large surface-to-volume ratio, fewer defects, and less strain makes it a potential material for development of high-performance nanoscale devices. β-Ga2O3 nanostructures have shown great promise for nanoscale devices such as deep-UV photodetectors, gas sensors, and FETs. In addition, functional nanowires based on β-Ga2O3 nanostructures can also be utilized for establishing the nanoscale device platform.
关键词： device applications,photodetectors,FETs,β-Ga2O3 nanostructures,gas sensors,growth techniques
更新于2025-09-09 09:28:46
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Gallium Oxide || Low-field and high-field transport in β-Ga2O3
摘要： β-Ga2O3 has recently emerged as a novel wide-bandgap semiconductor with immense potential for applications in power electronics and optoelectronics. Experimental advancements in the past 5 years have been significant toward realizing commercial β-Ga2O3 devices in the near future [1–7]. Matured crystal growth and processing techniques make the material further promising [8–10]. In terms of power electronic applications, MOSFETs based on this material have been demonstrated that could withstand record high voltages [11, 12]. The accuracy of n-type doping and the difficulty of p-type doping make electrons the primary charge carriers in β-Ga2O3. Although β-Ga2O3 has lower electron mobility compared to other wide-bandgap semiconductors, it is found to have a superior Baliga’s figure of merit that jointly accounts for on-state resistance and breakdown voltage [4]. So it is important to investigate in rigor the fundamentals behind β-Ga2O3 material properties that could be beneficial to gain an understanding on the causes that control mobility and breakdown voltage. There are theoretical reports on fundamental materials aspects including electronic structure [13] and optical properties [14], lattice dynamical and dielectric properties [15], and thermal properties [16, 17] as well. The primary physics behind both mobility (and hence the device on resistance) and breakdown voltage lies in the electron transport phenomenon. There have been a few experimental reports that try to characterize the electron transport and scattering mechanisms in β-Ga2O3 with Hall measurements being reported a few times to predict temperature dependence and also crystal orientation dependence of the electron mobility [18, 19]. On the other hand, we are making a systemic study on the theoretical understanding of electron transport in β-Ga2O3 starting from the first principles [20–22]. The main idea is to follow a bottom-up approach in order to develop an understanding of the near-equilibrium and far-from-equilibrium electron dynamics in β-Ga2O3. This is unique compared to conventional semiconductors in a way that β-Ga2O3 has a low-symmetry crystal structure and a fairly large primitive unit cell that gives rise to many phonon modes. On several occasions, the traditional notions of electron transport that are applicable to Si and GaAs actually do not quite hold well in the case of β-Ga2O3. In this chapter, we attempt to provide a comprehensive picture of electron transport in β-Ga2O3 under low and moderately high electric fields based on our work in the recent years.
关键词： electron-phonon interaction,β-Ga2O3,electron mobility,power electronics,optoelectronics,electron transport,velocity-field curves,wide-bandgap semiconductor
更新于2025-09-09 09:28:46
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Gallium Oxide || Electron paramagnetic resonance (EPR) from β-Ga2O3 crystals
摘要： Electron paramagnetic resonance (EPR) is often used to identify and characterize defects and impurities having unpaired spins in semiconductors and insulators [1–4]. Examples include donors, acceptors, vacancies, interstitials, antisites, small polarons, transition-metal ions, and rare-earth ions. Simply stated, an EPR spectrum represents the absorption of microwaves at discrete values of magnetic field. This allows the energy-level scheme of the unpaired spin system to be determined. The importance of EPR arises from its high sensitivity and high resolution. Depending on the line widths, concentrations of defects as low as a few parts per billion can be easily observed. Each paramagnetic defect has a unique EPR spectrum that reflects its g matrix and hyperfine matrices, as well as the zero-field splittings when S is greater than 1/2. Once the identity of the responsible defect has been established, a spectrum can be used to compare concentrations of the defect in different samples and also to monitor changes in the concentration of the defect during photoexcitations and thermal anneals.
关键词： Electron paramagnetic resonance,β-Ga2O3,defects,semiconductors,insulators,impurities
更新于2025-09-09 09:28:46
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Gallium Oxide || Hydrogen in Ga2O3
摘要： Semiconductors with bandgaps larger than the 3.4 eV bandgap of GaN are emerging as a new class of ultrawide-bandgap (UWBG) electronic materials [1–5]. In spite of the promising applications that are possible for UWBG materials, an understanding of their fundamental properties is at an early stage of development. The focus of this chapter is the hydrogen impurity and its interactions with other defects in β-Ga2O3, a transparent conducting oxide with an ultrawide bandgap of 4.9 eV [6–9]. (It is the most thermally stable monoclinic β phase of Ga2O3 to which we refer throughout this chapter.)
关键词： transparent conducting oxides,Hydrogen,defects,ultrawide-bandgap semiconductors,Ga2O3
更新于2025-09-09 09:28:46
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Gallium Oxide || Dry etching of Ga2O3
摘要： There is generally a need to pattern Ga2O3 when fabricating devices such as UV solar blind photodetectors, various types of transistors, as well as sensors [1, 2]. The patterning is carried out by etching the semiconductor, using dielectric or photoresist masks to protect the active areas. There are two basic classes of etch processes, those carried out in the liquid phase (known as wet etching) and those performed in the gas phase (called dry etching, especially when a plasma is used to provide the reactive species for etching) [3]. Etch processes may be classified by their rate, selectivity, uniformity, directionality (isotropy or anisotropy), surface quality, and reproducibility [3]. All etching processes involve three basic events: (i) movement of the etching species to the surface to be etched, (ii) chemical reaction to form a compound that is soluble in the surrounding medium, and (iii) movement of the by-products away from the etched region, allowing fresh etchant to reach the surface. Both (i) and (iii) usually are referred to as diffusion, although convection may be present. The slowest of these processes primarily determines the etch rate, which may be diffusion or chemical-reaction limited.
关键词： reactive ion etching,inductively coupled plasma,Ga2O3,plasma etching,dry etching
更新于2025-09-09 09:28:46
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Gallium Oxide || Band alignments of dielectrics on (? 201) β-Ga2O3
摘要： β-Ga2O3 is an attractive wide direct bandgap semiconductor ((cid:1)4.9 eV) for power electronics, truly solar blind UV detection, and extreme environment applications [1–16]. The β monoclinic conformation of Ga2O3 is the most prominent of the five phases; it is already available commercially in up to 4-in diameter wafers with prices expected to drop significantly over the next few years as processes are further refined and more crystal growth companies enter the market. α and ε conformations have proven to be more difficult in determining growth parameters. Hydride vapor-phase epitaxy (HVPE) has shown some promise for growth of both of these phases but much development is still needed. As such, all the discussion in this chapter is on the β-phase.
关键词： extreme environment applications,β-Ga2O3,UV detection,power electronics,HVPE,monoclinic conformation,bandgap
更新于2025-09-09 09:28:46
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Gallium Oxide || Radiation damage in Ga2O3
摘要： β-Ga2O3 has a large bandgap of approximately 4.9 eV and an estimated critical electric field (EC) strength of 8 MV/cm. The large bandgap of β-Ga2O3 allows high-temperature device operation and this large critical field allows high-voltage operation (relative to maximum breakdown) and the most common device structure reported to date has been Schottky rectifiers. This material also has potential in devices with low power loss during high-frequency switching in the GHz regime. Similarly, Ga2O3-based photodetectors are attracting interest for their promise as truly solar-blind deep ultraviolet (UV) photodetectors exhibiting cut-off wavelengths below 280 nm. These would have applications in detection of UV wavelengths for military applications, air purification, space communication, ozone-layer monitoring, and flame sensing.
关键词： β-Ga2O3,photodetectors,radiation damage,Schottky rectifiers,wide bandgap semiconductors
更新于2025-09-09 09:28:46
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Gallium Oxide || Ga2O3 nanobelt devices
摘要： β-Gallium oxide (β-Ga2O3) is attractive as a novel material for (opto)electronics, especially high-power electronics and solar-blind photodetectors (PDs). It has an ultrawide direct bandgap of around 4.8–4.9 eV at room temperature and high thermal and chemical stabilities [1, 2]. The theoretical electrical breakdown field (Ebr) of β-Ga2O3 is known to be (cid:1)8 MV/cm, and 3.8 MV/cm of Ebr has been experimentally demonstrated in a recent report, recording a higher value than those of GaN and SiC. Baliga’s figure of merit (BFOM) of β-Ga2O3 is also superior among some of the other popular wide-bandgap semiconductors, such as 4H-SiC and GaN [3–6]. These outstanding properties have led to a large number of reports on various electrical devices based on β-Ga2O3 including metal-oxide-semiconductor field-effect transistors (MOSFETs), metal-semiconductor field-effect transistors (MESFETs), and Schottky barrier diodes [7–10]. Furthermore, the wide bandgap of β-Ga2O3 provides intrinsic solar blindness that allows fabrication of solar-blind PDs without the need for additional optical filters that block light in the range of long wavelength [11]. Single-crystal β-Ga2O3 is commercially available as a various of growth methods exist; especially the edge-defined film-fed growth (EFG) method that can be used to grow bulk β-Ga2O3 substrates with high crystal quality [12, 13]. However, the low thermal conductivity of β-Ga2O3 has to be considered when fabricating high-power electrical devices.
关键词： high-power electronics,β-Ga2O3,wide-bandgap semiconductors,optoelectronics,solar-blind photodetectors
更新于2025-09-09 09:28:46
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Gallium Oxide || Ga2O3-photoassisted decomposition of insecticides
摘要： Recent years have witnessed an ever increase in the production of many insecticides that contain fluorine and/or trifluoromethyl groups [1]. These fluorinated chemicals have excellent physicochemical characteristics such as, adsorption, hydrophobicity, thermal chemical stability, and bioactivity [2]. Accordingly, they have attracted intense investigations and have been applied in various fields [3]. Reports have appeared regarding contamination of common insecticides, health risks, and pollutant-treatment systems. However, scant research is being carried out on the decomposition of fluorinated substances. The perfluorinated chemicals such as perfluorooctanoic acid (PFOA) and the perfluorooctanesulfonate (PFOS) surfactant were produced by DuPont in the United States in 1947. Seven decades have elapsed since their developments [4]. PFOA and PFOS have also been used in firefighting water sprays in great amounts resulting in the worldwide contamination of aquatic environments. Because the quantities used were low in the beginning, people failed to recognize the potential hazards of these perfluorinated chemicals. Yet recently the production has increased considerably with its inevitable serious ecological and environmental results caused by the use of these fluorinated chemicals.
关键词： photocatalytic degradation,wastewater treatment,fluorinated chemicals,Ga2O3,insecticides
更新于2025-09-09 09:28:46
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Gallium Oxide || Ga2O3-based gas sensors
摘要： β-Ga2O3 has recently gained a lot of interest for applications in solar-blind deep ultraviolet (UV) detectors and high-power electronics at elevated temperatures. The interest stems from its intrinsic material properties, such as wide-bandgap nature (4.9 eV) and high breakdown electric field. β-Ga2O3 can also serve as a reactive oxide layer, sensitive to a wide variety of gases, especially at high temperatures in harsh environments. Many β-Ga2O3-based gas sensors have been reported recently [1–20]. In this chapter, the gas sensing mechanism and the sensing characteristics of β-Ga2O3 are reviewed. First, the material properties of β-Ga2O3 are reviewed for a clear understanding of surface reactions at oxide surfaces with various gas molecules. The crystal structure of β-Ga2O3 and the surface atomic configurations of 201 and (010)-oriented β-Ga2O3 are investigated. The wet and dry etching characteristics and the metal contact properties of 201 and (010) β-Ga2O3 single crystals are discussed for a broad range of device applications. Recent reports of β-Ga2O3-based hydrogen sensors are discussed, and the hydrogen sensing properties of 201 and (010) β-Ga2O3 single crystals are compared for enhanced hydrogen detection.
关键词： crystal structure,β-Ga2O3,high-temperature applications,wet and dry etching,Ohmic contact,gas sensors,hydrogen sensors
更新于2025-09-09 09:28:46