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Capture and, subsequently, in situ characterization of microparticles generally require complex fabrication processes and sophisticated techniques in microfluidic devices. In this paper, we present a simple and inexpensive technique for capturing and applying chemical agents to individual charged microparticles with the same glass microelectrode in a circular microfluidic channel. The microfluidic device features a thin poly-dimethyl-siloxane (PDMS) layer (100 µm, thickness) above the circular channel (diameter, 50 µm) so that the tip of the glass microelectrode can enter into the channel by penetrating through the thin PDMS layer. When an electric field is applied across the tip of the microelectrodes, the tip can capture charged microparticles or living cells that are flowing through the channel. Meanwhile, the same glass microelectrode can be used to apply chemical agents to the captured particles or living cells by filling the solution of the chemical agent into its tip. This simple design method offered simple fabrication without the need for any specialized equipment for the manipulation of charged particles or living cells in controlled microenvironments. [ABSTRACT FROM AUTHOR]

This paper demonstrates the improvement of device linearity in AlGaN/GaN heterostructure field effect transistors (HFETs) using polarization Coulomb field (PCF) scattering and investigates the relationship between device linearity and PCF scattering under 10 and 20 V drain bias. The mobility of the gate-to-source region in AlGaN/GaN HFETs is calculated using the Monte Carlo method. We find that PCF scattering decreases with an increase in gate bias (from −3 to −0.5 V) under high field conditions, leading to lower gate-to-source resistance. Under 20 V drain bias, linearity is worse than under 10 V drain bias. The transconductance drop is significant in AlGaN/GaN HFETs, which damages linearity. By adopting an appropriate drain bias, PCF scattering can alleviate transconductance drop and improve the linearity of AlGaN/GaN HFETs. [ABSTRACT FROM AUTHOR]

In this study, a split-gate AlGaN/GaN heterostructure field-effect transistor with an auxiliary gate was fabricated. Through experiment and analysis, it was discovered that by applying a constant potential (usually 0 V or negative potential) to the auxiliary gate, a negative bias can be formed between the auxiliary gate and the channel. This consumes the two-dimensional electron gas in the channel, leading to significant improvements in the saturation characteristics of split-gate devices. By applying different potentials to the main gate and the auxiliary gate, a variety of device working modes can be obtained, and the threshold voltage can be altered across a large range. These advantages make split-gate devices with auxiliary gates more suitable for increasingly complex integrated circuit applications. [ABSTRACT FROM AUTHOR]