- 标题
- 摘要
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- 实验方案
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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 || 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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European Microscopy Congress 2016: Proceedings || A micro-combinatorial TEM method for phase mapping of thin two-component films
摘要： The aim is to introduce a new method for the preparation and investigation of thin films of composite materials, specifically focusing on the synthesis and characterization of two-component thin films for optoelectronic applications. The study explores the potential of these materials in enhancing the performance of optoelectronic devices, such as solar cells and LEDs, by improving their efficiency and stability under various environmental conditions.
关键词： LEDs,optoelectronics,solar cells,composite materials,thin films
更新于2025-09-04 15:30:14
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Twist-angle Dependent Optoelectronics in a few-layer Transition-Metal Dichalcogenides Heterostructure
摘要： Lattice matching has been supposed to play an important role in the coupling between two materials in vertical heterostructure (HS). To investigate this role, we fabricated a heterojunction device with a few layers of p-type WSe2 and n-type MoSe2 with different crystal orientation angles. The crystal orientations of WSe2 and MoSe2 were estimated by using high-resolution X-ray diffraction. Heterojunction devices were fabricated with twist angles of 0?, 15? and 30?. The I-V curve of the sample with the twist angle of 0° under the dark condition showed a diode-like behavior. The strong coupling due to lattice matching caused a well-established p-n junction. In cases of 15° and 30° samples, the van der Waals gap was built due to lattice mismatching, which resulted in the formation of a potential barrier. However, when the LED light of 365 nm (3.4 eV) was illuminated, excited electrons and holes were possible to jump beyond the potential barrier and the current flowed well in both forward and reverse directions. The effects of the twist angle were analyzed by spectral responsivity and external quantum efficiency, where it was found that the untwisted HS exhibited higher sensitivity under IR illumination while the twisting effect was not noticeable under UV illumination. From the photoluminescence and Raman spectroscopy, it was confirmed that the twisted HS showed a weak coupling due to the lattice mismatch.
关键词： p-n junction,optoelectronics,transition-metal dichalcogenides,heterostructure,a few-layer TMD,twist angle
更新于2025-09-04 15:30:14
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Direct and photon-assisted tunneling in resonant-cavity quantum-well light-emitting transistors
摘要： Tunneling in a transistor is a critical quantum process toward the next-generation, energy-efficient, high-speed data transfer for both electrical and optical communications. In this work, resonant-cavity quantum-well light-emitting transistors with tunneling collector junctions are designed and fabricated. Three distinctive tunneling mechanisms are clearly identified by the transistor optical output family curves, namely, electron direct tunneling (DT) from collector to base, electron DT from base to collector, and intra-cavity photon-assisted electron tunneling from base to collector. The device operations under both direct and photon-assisted tunneling are explained in detail by the intra-cavity quantum transition of electron-hole pair to photon dynamics. The tunnel junction and the corresponding carrier tunneling injection suggest the possibility of utilizing tunneling to achieve high-speed optoelectronics operations.
关键词： photon-assisted tunneling,optoelectronics,quantum-well,resonant-cavity,light-emitting,transistor,tunneling
更新于2025-09-04 15:30:14
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Influence of rare earth material (Sm3+) doping on the properties of electrodeposited Cu2O films for optoelectronics
摘要： Herein, we report samarium (Sm) dopant concentration effect on Cu2O films characteristics prepared by electrodeposition method. XRD patterns of the films indicated that pristine and Sm:Cu2O films have polycrystalline cubic structure with (111) preferred orientation. It was seen from the SEM photographs pinhole free dense triangle shaped grains for undoped Cu2O thin films and the grain size was decreased as concentration of samarium was increased. Raman spectroscopy showed peaks at 108, 146, 217, 413 and 637 cm?1 which conformed the Cu2O phase formation and intensity of the peaks was decreased with a increase in dopant concentration. UV–Vis spectra exhibited that the absorption value of Cu2O films is increased gradually with reduction in band gap value for the increase of samarium content. Photoluminescence (PL) spectra revealed that all films display a visible light emissions and its intensity was reduced due to increase in doping concentration. Photosensitivity observation study indicated that the photocurrent of deposited Cu2O films was increased along with the increase in dopant material concentration.
关键词： Electrodeposition,Cu2O films,Optoelectronics,Structural properties,Samarium doping,Optical properties,Photosensitivity
更新于2025-09-04 15:30:14