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To improve the power handling capability at ground stations of a 5.8-GHz solar space power satellite using microwave power transmission, a power charge-pump meta-semiconductor field-effect transistor (MESFET)-based rectifier is presented in this article. Unlike conventional microwave Schottky diodes, diode-connected MESFETs, whose nonlinear characteristics help them to have a unique current–voltage (I-V) curve that overcomes the limitations of a Schottky diode. Thus, the maximum input power of the proposed rectifier is extended up to 251.2 mW by replacing a Schottky diode with a diode-connected MESFET. Additionally, a class F harmonic processing network is introduced to control the voltage and current waveform at the load of the rectifier. Consequently, the RF-dc conversion efficiency is increased since the power dissipation is limited at the junction resistance of both the drain and the source of the MESFET. Owing to the abnormal characteristics of the diode-connected MESFET, the measured conversion efficiency of our rectifier is approximately 73.2% at 126 mW, and the input power range for rectifier efficiency higher than 50% is between 16 and 224 mW. The proposed rectifier for the space solar power satellite application is demonstrated and verified using a microwave wireless power transmission system. [ABSTRACT FROM AUTHOR]

In this letter, fin-shape tri-gate $\beta $ -Ga2O3 lateral MESFETs are demonstrated with a high power figure of merit (PFOM) of 0.95 GW/cm2 – a record high for any $\beta $ -Ga2O3 transistor to date. A low-temperature un-doped buffer-channel stack design is developed which demonstrates record high Hall and drift electron mobilities in doped $\beta $ -Ga2O3 channels allowing for low ON resistances (RON) in $\beta $ -Ga2O3 MESFETs. Fin-widths (Wfin) were 1.2- $1.5~\mu \text{m}$ and there were 25 fins (Nfin) per device with a trench depth of $\sim ~1~\mu \text{m}$. A $\beta $ -Ga2O3 MESFET with a source-drain length of 6.4 $\mu \text{m}$ exhibits a high ON current (187 mA/mm), low RON ($20.5~\Omega $.mm) and a high average breakdown field (4.2 MV/cm). All devices show very low reverse leakage until catastrophic breakdown for breakdown voltages (VBR) scaling from 1.1kV to ~3kV. This work demonstrates the potential of channel engineering in improving $\beta $ -Ga2O3 device performance towards lower conduction losses for low-to-medium voltage applications. [ABSTRACT FROM AUTHOR]

We demonstrate a passivated MESFET fabricated on (010) Si-doped $\beta $ -Ga2O3 with breakdown over 2.4 kV without field plates, high Power Figure of Merit (PFOM), and high estimated Huang’s Material Figure of Merit (HMFOM), owing to low gate charge and high breakdown. MESFETs with 13 $\mu \text{m}$ source-drain spacing and 75 nm channel exhibited a current density of 61 mA/mm, peak transconductance of 27 mS/mm, and on-resistance of ${133}~\Omega \cdot \text {mm}$. The device showed a PFOM competitive with state-of-the-art $\beta $ -Ga2O3 devices and a record high estimated HMFOM for a $\beta $ -Ga2O3 device, competitive with commercial wide-band gap devices. This demonstrates high-performance $\beta $ -Ga2O3 devices as viable multi-kV high-voltage power switches. [ABSTRACT FROM AUTHOR]

A high-performance solar-blind phototransistor, which is based on hydrogen-terminated diamond was fabricated and reported. The fabricated phototransistor was based on metal–semiconductor field effect transistor architecture with a high photoresponsivity ($2.48\times10$ 4 $\text{A}/\text{W}$), high external quantum efficiency ($1.44\times10$ 5), and high detectivity ($5.08\times10$ 9 Jones) under 213-nm light illumination (437 $\text{W}/\text{m}$ 2). At 5240 $\text{W}/\text{m}$ 2 light illumination, the change in drain current exceeds six orders of magnitude. Through transient response measurement, the rise/decay time of the phototransistor is about 88/36 ms and there is no significant persistent photoconductive effect. [ABSTRACT FROM AUTHOR]

We fabricated AlN metal semiconductor field effect transistors (MESFETs) with an epitaxially grown n-type AlN channel layer and characterized the temperature dependence of their device properties. As the temperature was varied from room temperature to 500°C, maximum drain current increased from 0.42 to 45 mA/mm and maximum transconductance increased from 0.05 to 4.5 mS/mm. This enhanced device performance with increasing temperature is attributed to increased carrier concentration in n-type AlN due to the large ionization energy of Si donors. Owing to a large Schottky barrier height of 2.08 eV for the Ni gate electrode/n-type AlN interface, reverse leakage current is less than $10^{-{10}}$ A/mm at temperatures ranging from room temperature to 500°C. Off-state breakdown voltage is as high as 1720 V for gate-drain spacing of 16 ${\mu }\text{m}$. These results indicate that AlN MESFETs are promising for high-voltage electronic devices operating at high temperature. [ABSTRACT FROM AUTHOR]