Gallium nitride- (GaN) based high electron mobility transistors (HEMTs) provide a good platform for biological detection. In this work, both Au-gated AlInN/GaN HEMT and AlGaN/GaN HEMT biosensors are fabricated for the detection of deoxyribonucleic acid (DNA) hybridization. The Au-gated AlInN/GaN HEMT biosensor exhibits higher sensitivity in comparison with the AlGaN/GaN HEMT biosensor. For the former, the drain-source current ( V) shows a clear decrease of 69 μA upon the introduction of 1 μmolL (μM) complimentary DNA to the probe DNA at the sensor area, while for the latter it is only 38 μA. This current reduction is a notable indication of the hybridization. The high sensitivity can be attributed to the thinner barrier of the AlInN/GaN heterostructure, which makes the two-dimensional electron gas channel more susceptible to a slight change of the surface charge.

InAlN/AlN/GaN HEMTs with both source and gate dual field-plates (FPs) are proposed. To investigate the influence of dual FPs on the devices characteristics, two types of devices with gate FP and without FPs were fabricated and tested. The devices were subjected to different kinds of short-term direct current bias (DC-bias) stress conditions. The results show that after the off-state bias stress, the drain current reduction rate of the devices with dual FPs was 3.32%, which was less than that in both devices with a gate FP of 7.57% and devices without FPs of 14.63%. The current collapse of the HEMTs with dual FPs was relieved due to the increase of electric field uniformity between the gate and drain. The degradation of the output characteristics was more serious after the on-state bias stress. In addition, the effects of bias stress on the transfer characteristics of the devices were studied, and the trapping processes under different stress conditions in the devices were discussed.

We report on fabrication and photovoltaic characteristics of In𝑥Ga1−𝑥N/GaN multiple quantum well solar cells with different indium compositions and barrier thicknesses. The as-grown samples are characterized by highresolution x-ray diffraction and reciprocal space mapping. The results show that the sample with a thick barrier thickness (10.0 nm) and high indium composition (0.23) has better crystalline quality. In addition, the dark current density-voltage (𝐽-𝑉 ) measurement of this device shows a significant decrease of leakage current, which leads to high open-circuit voltage 𝑉oc. Through the 𝐽-𝑉 characteristics under an Air Mass 1.5 Global (AM 1.5 G) illumination, this device exhibits a 𝑉oc of 1.89 V, a short-circuit current density 𝐽sc of 3.92 mA/cm 2 and a fill factor of 50.96%. As a result, the conversion efficiency (𝜂) is enhanced to be 3.77% in comparison with other devices.