A red nanowire LED with an InGaN bulk active region, directly grown on a p-Si (111) substrate, is demonstrated. The LED exhibits relatively good wavelength stability upon increasing injection current and narrowing of the linewidth without quantum confined Stark effect. Efficiency droop sets in at relatively high injection current. The output power and external quantum efficiency are 0.55 mW and 1.4% at 20 mA (20 A/cm2) with peak wavelength of 640 nm, reaching 2.3% at 70 mA with peak wavelength of 625 nm. The operation on the p-Si substrate results in large carrier injection currents due to a naturally formed tunnel junction at the n-GaN/p-Si interface and is ideal for device integration.

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As a typical kind of special robot with high flexibility and maneuverability, the hyperredundant manipulators (HRM) which can work in the narrow and complex space arose much related research work. Due to the particularity of the environment and the structural complexity of the manipulators, there are many problems for the HRM in specific applications. This paper summarizes some representative research works for HRM, including the mechanical design, environment perception, robotic navigation, and trajectory control. In order to make the design of the HRM systems more suitable for applications, the technical problems of current research are analyzed to address the key issues for the improvement. Finally, the prospect of spatial reachability, structural compactness, operation accuracy, and interaction friendliness of hyperredundant manipulators are presented.