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Future Prospects
Published in Gourab Majumdar, Ikunori Takata, Power Devices for Efficient Energy Conversion, 2018
Gourab Majumdar, Ikunori Takata
With the latest status of the IGBT being that it is the de facto power switch component for power electronics applications, the question arises as to the extent to which the IGBT’s performance can be improved. Or what could possibly be the next device solution after the IGBT? Would it still be based on silicon? Or is it going to be realized by using a new material such as silicon carbide (SiC)? Although answers to these questions shall invariably depend on the market needs, a numerous number of researchers and engineers are engaged globally in advancing wide-bandgap (WBG)-material- based device solutions to a practical level as earliest as possible. The prospective candidates from the WBG group are considered to be SiC, gallium nitride (GaN), aluminum nitride (AlN), gallium oxide (Ga2O3), and diamond (C). Out of such possible postsilicon semiconductor materials for power devices, the most promising one till date is SiC, followed by GaN. In this chapter, application of the former for practical power module productization will be discussed in detail. Figure 4.2 is a review of Fig. 4.1 that includes comparisons of extrapolated theoretical and practical limits for silicon and SiC- based devices, indicating as well expectations from the use of SiC as the postsilicon material of choice.
Common methods for the preparation of clean A- and B-type GaN surfaces assessed by STM, RHEED and XPS
Published in A. G. Cullis, P. A. Midgley, Microscopy of Semiconducting Materials 2003, 2018
R A Oliver, C Nörenberg, M G Martin, A Crossley, M R Castell, G A D Briggs
also covered in a layer of gallium oxide. The reduction in the stoichiometry of the samples after sputterannealing, and the change in the surface morphology, suggests that this has now been removed. However we are not yet able to identify the composition of the interlinking islands on this surface.
Fabrication processes
Published in Frédéric Guittard, Thierry Darmanin, Bioinspired Superhydrophobic Surfaces, 2017
Frédéric Guittard, Thierry Darmanin
High-density GaN nanowires were also prepared using gallium, gallium oxide, and graphite. Using N2 as gas flow and at 960°C, GaN nanowires were observed after 30 min [783]. The as-prepared GaN nanowires were superhydrophobic (θw = 155°), became superhydrophilic after UV irradiation and became superhydrophobic again after dark storage or heating. Moreover, the authors also observed the possibility of modulating protein and cell adhesion by UV irradiation.
Photon Activation Analysis in Gallium, Nickel, and Vanadium
Published in Nuclear Science and Engineering, 2023
Robert Bentley, Geno Santistevan, Douglas Wells, Andrew Hutton, Adam Stavola, Steve Benson, Kevin Jordan, Joe Gubeli, Pavel Degtiarenko, Lila Dabill
This paper serves to highlight the preliminary production methods and reaction cross sections regarding these two interesting isotopes. Two independent irradiations were done on three target materials. These included a V foil, natural nickel foil, and a gallium oxide powder. The powder was replaced with a more isotopically pure Ga pellet in the second irradiation. The powder is an affordable alternative to Ga pure, serving as an excellent probe into the activation of higher-cost targets. The composition is approximately 98.78% Ga to 1.22% Ga. This irradiation serves as a baseline calibration run prior to a secondary run with a 99.60% Ga to 0.40% Ga pellet. Furthermore, the radiochemical separation of Cu to all other isotopes is to be demonstrated. Comparisons were made to the FLUKA-2020 particle transport code.29,30 Initial model runs with FLUKA-2020 will provide insights as to the expected activities at various beam energies and powers.
Oxidation behavior with quantum dots formation from amorphous GaAs thin films
Published in Philosophical Magazine, 2018
Srikanta Palei, Bhaskar Parida, Keunjoo Kim
The GaAs crystal has the band gap of 1.42 eV, and gallium oxide has large bandgap energy of around 4.9 eV [3]. It has been reported that arsenolites of cubic arsenic oxide have optical PL peaks at 548 nm (2.26 eV), 615 nm (2.016 eV), and 505 (2.45) −650 nm (1.90 eV) in the near-field photoluminescence measurements [10,11]. These PL spectra are related to defect centres in the band gap region. However, the calculated bandgap of arsenolite by first-principles lattice-dynamics calculations is 3.64 eV for <100> and 4.01 eV for <111> directions in the dynamically stable low-symmetry structures, where valence electrons localise and form a lone pair of cations [33]. The band gap of 2.73 eV from UPS-IPS data and large PL emission energy of 3.0 eV are not consistent with the energy structures of oxides. However, it is valuable to analyze the quantum size effect for both band gap energy and PL emission energy. The emission energy from the GaAs quantum dot is expressed by the Brus equation of effective mass approximation (EMA) [34]: , where R is radius, is the bulk band gap energy of 1.42 eV, and are the effective electron and hole masses of 0.063 and 0.51 , respectively. Therefore, from GaAs quantum dot equation of , the PL energy of 2.41–2.75 eV corresponded to a dot diameter of 4.48–5.19 nm and the energy band gap of 2.73 eV corresponded to the diameter of 4.52 nm. These results are consistent with the TEM image shown in Figure 3(d).
Scanning the Issue
Published in IETE Journal of Research, 2023
Arun Kumar, Shiban K Koul, Ranjan K Mallik
The paper on “DC Characterization and High-Frequency Performance Analysis of a GaN/AlGaN HET on a β-Ga2O3 Substrate” presents the design of an AlGaN/GaN heterojunction transistor on a wide band gap material substrate viz. β gallium oxide. It also presents the simulation performance study using Silvaco TCAD software. The paper presents the cutoff frequency and maximum oscillation frequency estimates that are used to draw inferences about the high electron mobility transistor’s suitability for radio frequency applications.