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Herein, we designed several structures of GaAs/AlGaAs extended gate high electron mobility transistors (EG-HEMT) for cTnI detection, in order to explore the mechanism of bio-detection, the limit of detection (LOD) as well as the application in clinical detection. The experiment carried out that 50y structure of EG-HEMT biosensor, whose extended electrode is 50 times as large as the gate, has highest biological regulation ability ($\delta $). Meanwhile, the concentration range of cTnI detection using 50y EG-HEMT biosensor is about 100 fg ml−1 to $10~\mu \text{g}$ ml−1, which is much broader than that of Unicel Dxl800 (usually be used in clinical detection). Furthermore, due to the influence of parasitic resistance and other factors, $\delta $ increases with the increase of y, but the rising rate of $\delta $ decreases at the same time. By comparing the detecting results of clinical samples, 30y EG-HEMT is the best in the detection of cTnI concentration with a relative error of 6%. In a higher concentration range, it is more accurate than that of the Unicel Dxl800, breaking through its limit. [ABSTRACT FROM AUTHOR]

A reverse-channel 4H-SiC trench gate metal-oxide-semiconductor field-effect transistor (UMOSFET) (RC-MOS) is proposed in this article. The RC-MOS is demonstrated to have low specific ON-resistance (RON,sp) by numerical simulation. The trench oxide in the RC-MOS is fully protected by the n+ source, the p-shield, and the p-base regions. Thus, a reduced trench corner field far below 3 MV/cm can be achieved in both the OFF- and ON-state. Furthermore, the gate-to-drain charge (QGD) of the RC-MOS is 33 nC/cm2, which is much lower than that of the dual buffer layer MOSFET (DB-MOS), owing to little overlap between the gate and drain electrodes. Consequently, the RC-MOS exhibits the superior figures of merit QGD × RON,SP = 82m Ω ⋅ nC. Due to the low reverse transfer capacitance and gate charges in the RC-MOS, the total switching loss of $570~μJ/cm2 is decreased by 64.5% in comparison to that of the DB-MOS. These superior properties show that the proposed UMOSFET can be a good candidate for further improvements in the gate oxide reliability and high-frequency performance of SiC MOSFETs. [ABSTRACT FROM AUTHOR]

A silicon carbide (SiC) injection enhanced gate transistor with accumulation channel (AC-IEGT) is proposed in this letter, which has a barrier layer with small windows under the p+ shielding region. The new structure can enhance electron injection through accumulation channel. Thus, an optimized carrier density can be obtained in the emitter side. Compared with conventional SiC insulated gate bipolar transistor and carrier stored trench bipolar transistor, static simulation results show that the static characteristics of the device are improved significantly. The figure of merit ( V\text {BR}^{2}/R\text {on,sp}) of AC-IEGT increases by 81.96 % and 17.78 %, respectively. The mix-mode circuit simulation results show that the proposed could be more suitable for ultra-high voltage application. [ABSTRACT FROM AUTHOR]

InGaN light-emitting diodes (LEDs) with the alternating quantum barriers (AQB) of AlGaN and InGaN is proposed for LED applications. With this design, simulation results show that the carrier concentration and transport in the multi-quantum well (MQW) active region are improved and accordingly, the radiative recombination rate is enhanced and the electron leakage is suppressed, due to the appropriate band engineering. Thus, the proposed structure shows an efficient improvement in the internal quantum efficiency (IQE) and efficiency droop, compared to the original structures with GaN barriers, or AlGaN barriers, or InGaN barriers. Our studies suggest that relatively simple engineering of the MQW region may still have notable positive effects on LED performance. [ABSTRACT FROM PUBLISHER]

In InGaN-based light-emitting diodes (LEDs), some specific designs on the quantum barrier layers by alternating AlGaN barriers with GaN barriers are proposed. Compared with the original structures with GaN barriers or AlGaN barriers, the proposed structure shows significant improvement in internal quantum efficiency (IQE) and efficiency droop, due to the better hole injection/transportation and electron confinement of the multiquantum well active region, and accordingly suppressed electron leakage, which provides us a simple but highly effective approach for high-performance LED applications. Moreover, the simulation suggests that the IQE and power can be further enhanced without efficiency droop when our designed structure is with increasing Al composition because of the uniformly dispersed carriers, permitting more freedom for the optimization. [ABSTRACT FROM PUBLISHER]

Alpha-fetoprotein (AFP) is a typical tumor marker in early diagnosis. Highly specific detection of the AFP was demonstrated using AlGaAs/GaAs high electron mobility transistors (HEMTs). Anti-AFP antibody was immobilized to the Au-coated gate area of the HEMT by a covalent modification method. To avoid any nonspecific binding, the gate was blocked by bovine serum albumin after the reduction of the carbonyl group. A detection limit for the AFP as low as a few picograms/milliliter was achieved, and cross reactivity of the sensor was found negligible, demonstrating its high selectivity. Successful detection with minute quantity of the sample indicates that the sensor has great potential in practical screening for a wide population. [ABSTRACT FROM AUTHOR]

4H-SiC-based metal–insulator–semiconductor (MIS) ultraviolet (UV) photodetectors with thermally grown \SiO2 and evaporated \Al2\O3\/\SiO2 (A/S) films are fabricated and demonstrated as normally-off and normally-on mode devices, respectively. Ultralow dark currents of \3.25 \times \10^-10 and \9.75 \times \10^-9\ \A/cm^2 and high UV-to-visible rejection ratios of >\2 \times \10^3 have been achieved at 10 V. The peak responsivities of these devices were separately 30 mA/W at 260 nm and 50 mA/W at 270 nm at 10 V. These results demonstrate that S/4H-SiC and A/S/4H-SiC MIS photodetectors are promising candidates to be applied in optoelectronic integrated circuits. [ABSTRACT FROM AUTHOR]