Search

The simulations and experiments for two 400 W low‐speed direct‐drive permanent magnet synchronous generators (PMSGs) installed in a Floating Kuroshio Turbine (FKT) were implemented. The towing tank experiments were carried out at National Taiwan University. A generator can start to harvest current energy at the rotation speed of 30 rpm (corresponding to the current flow rate of 0.36 m/s), and produce the rated power of 400 W at 150 rpm. The speed is very low compared with the published reports. The energy conversion efficiency of the FKT is up to 0.85. The results show that the generated direct current (DC) power is more than 800 W at a flow rate of 1.5 m/s. The power coefficient for the FKT is about 0.4. The energy loss at each stage and the power difference between the testing platform and the towing tank experiment were also analyzed. Moreover, the shape of the FKT is a new design. Compared with other structures, the proposed FKT can easily follow the direction of the ocean current and the depth of the FKT can be adjustable; when it doesn't operate, it will float on the surface so that it is easy for maintenance. [ABSTRACT FROM AUTHOR]

This work demonstrates a trench isolated lateral double-implanted MOSFET (LDMOS) on Si-face in 4H-silicon carbide (SiC). A device $\vphantom {_{\int _{}}}$ where ${L}_{\textit {ch}} = 0.8\,\,\mu \text{m}$ and ${L}_{d} = 12\,\,\mu \text{m}$ shows an ${R}_{ \mathrm{\scriptscriptstyle ON},\text {sp}}$ of 22.9 $\text{m}\Omega $ cm2 at a ${V}_{\text {GS}}$ of 20 V and a breakdown voltage (BV) of 1100 V, corresponding to a high BV2/ ${R}_{ \mathrm{\scriptscriptstyle ON},\text {sp}}$ of 55.5 MW/cm2. Devices that have different ${L}_{\text {ch}}$ , ${L}_{\text {JFET}}$ , ${L}_{d}$ , and P-top dose values are measured in order to investigate the effects of geometry on the static performance. Operations at 150 °C are measured to evaluate the temperature performance. Gate charge waveforms are also measured in order to include the switching performance in the evaluation. The ${R}_{ \mathrm{\scriptscriptstyle ON}} \times {Q}_{G}$ and ${R}_{ \mathrm{\scriptscriptstyle ON}} \times {Q}_{\text {GD}}$ values are calculated as 17.7 and $9.0~\Omega $ nC, respectively, which are promising for power-integrated circuit applications. [ABSTRACT FROM AUTHOR]

Herein, solution‐processed indium gallium zinc oxide (IGZO) thin‐film transistor (TFT) is fabricated utilizing metal nitrates as precursors, and the impact of nitrate ions in different solvents on the performances of IGZO TFT is demonstrated. During IGZO film fabrication, the nitrogen in nitrate species actually dopes into the film in the fashion of different chemical states depending on different solvents. When IGZO precursors dissolve in deionized water (DIW), due to the high polarity of the solvent, metal nitrates are completely dissociated, leading to the conversion of nitrates to nitrides in IGZO film. This nitrogen decreases the density of the interface trap states, thus improving the characteristics of the IGZO TFT. In contrast, when using 2‐methoxyethanol (2‐ME) as the solvent, nitrogen mainly forms nitrogen oxide and acts as a trap density that leads to the degradation of the device performances. By increasing the annealing temperature of IGZO film, nitrogen oxide can convert to metal nitride, resulting in enhanced device performance. The IGZO TFT fabricated using DIW as a solvent with 300 °C annealing temperature exhibits the saturation mobility of 2.5 cm2 V−1 s−1 and Ion/off ratio of >106.5. Herein, a step is made toward the solvent effect on the performance of solution‐processed oxide TFT. [ABSTRACT FROM AUTHOR]

In this paper, a comparison of different techniques for SiC high-voltage devices is performed using numerical simulations. In particular, the method of counter doping (CD) introduced in the junction termination extension (JTE) region to create a multizone termination effect is investigated. Simulation shows that compared with the other edge termination techniques, CD-JTE greatly reduces the sensitivity of breakdown voltage (BV) to JTE doses and surface charges. The multizone CD-JTE with outer rings shows that for a 30- \mu m thick epi-layer, 90% of the theoretical BV is achievable with a wide tolerance of 11\,\times \,10^{\mathrm {12}} /cm ^{2} to the JTE dose and 85% of the theoretical BV with an increased tolerance of 6.19\times 10^\mathrm 12 /cm ^2 to the positive surface charges, both superior to other JTE structures investigated in this paper. [ABSTRACT FROM AUTHOR]