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Surface plasmon polaritons (SPPs) have become a research hotspot due to their high intensity and subwavelength localization. Through free-electron excitation, a portion of the momentum of moving electrons can be converted into SPPs. Converting highly localized SPPs into a radiated field is an approach with the potential to aid in the development of a light radiation source. Reducing losses of SPPs is currently a critical challenge that needs to be addressed. The lifetime of SPPs in metal films is longer than that in metal blocks. Traditional optical gratings can transform SPPs into radiation to avoid the decay of SPPs in metal; however, they are created by etching metal films, so they tend to alter the dispersion characteristics of these films and will emit radiation in the direction perpendicular to the metal surface. This paper proposes an approach to converting the SPPs of a metal film excited by free electrons into a radiation field via lateral grating and obtaining in-plane radiation. We investigate the properties of SPP lateral radiation. The study of lateral radiation from metal films holds significant importance for SPP radiation sources and SPP on-chip circuit development.

This article presents the utilization of the chemical–mechanical polishing (CMP) method to fabricate high-performance N-polar GaN/AlGaN metal–insulator–semiconductor high-electron-mobility transistors (MIS-HEMTs) through layer transfer technology. The nucleation and buffer layers were removed via CMP to attain a pristine N-polar GaN surface with elevated smoothness, featuring a low root-mean-square (RMS) roughness of 0.216 nm. Oxygen, carbon, and chlorine impurity elements content were low after the CMP process, as detected via X-ray photoelectron spectroscopy (XPS). The electrical properties of N-polar HEMTs fabricated via CMP exhibited a sheet resistance (Rsh) of 244.7 Ω/sq, a mobility of 1230 cm2/V·s, and an ns of 2.24 × 1013 cm−2. Compared with a counter device fabricated via inductively coupled plasma (ICP) dry etching, the CMP devices showed an improved output current of 756.1 mA/mm, reduced on-resistance of 6.51 Ω·mm, and a significantly reduced subthreshold slope mainly attributed to the improved surface conditions. Meanwhile, owing to the MIS configuration, the reverse gate leakage current could be reduced to as low as 15 μA/mm. These results highlight the feasibility of the CMP-involved epitaxial layer transfer (ELT) technique to deliver superior N-polar GaN MIS-HEMTs for power electronic applications.

A high-performance temperature sensor based on a p-GaN/AlGaN/GaN hybrid anode diode (HPT-HAD) fabricated by hydrogen plasma treatment is demonstrated. The sensor exhibits accurate and stable temperature responses from 73 to 573 K. The forward anode voltage is linearly proportional to the temperature over the measured temperature range at a fixed current. At a forward current density of 10−7 mA/mm, the device achieves a maximum sensitivity of 1.93 mV/K. The long-time anode current stress measurement reveals that the HPT-HAD shows almost no degradation even at 573 K for 1 h at a current of 100 μA, and the anode voltage shifts only 120 mV at 573 K for 1000 s at 1 nA. This work shows that the HPT-HAD temperature sensor can be reliably operated over a wide temperature range from cryogenic to high temperatures, so can be used in a variety of extreme environments.