Impact of electrostatic doping on carrier concentration and mobility in InAs nanowires

Recent progress of group III-V materials-based nanostructures for photodetection

Due to the suitable bandgap structure, efficient conversion rates of photon to electron, adjustable optical bandgap, high electron mobility/aspect ratio, low defects, and outstanding optical and electrical properties for device design, III-V semiconductors have shown excellent properties for optoelectronic applications, including photodiodes, photodetectors, solar cells, photocatalysis, etc. In particular, III-V nanostructures have attracted considerable interest as a promising photodetector platform, where high-performance photodetectors can be achieved based on the geometry-related light absorption and carrier transport properties of III-V materials. However, the detection ranges from Ultraviolet to Terahertz including broadband photodetectors of III-V semiconductors still have not been more broadly development despite significant efforts to obtain the high performance of III-V semiconductors. Therefore, the recent development of III-V photodetectors in a broad detection range from Ultraviolet to Terahertz, and future requirements are highly desired. In this review, the recent development of photodetectors based on III-V semiconductor with different detection range is discussed. First, the bandgap of III-V materials and synthesis methods of III-V nanostructures are explored, subsequently, the detection mechanism and key figures-of-merit for the photodetectors are introduced, and then the device performance and emerging applications of photodetectors are provided. Lastly, the challenges and future research directions of III-V materials for photodetectors are presented.

Measuring thermal conductivity of nanostructures with the 3ωmethod: the need for finite element modeling

Conventional techniques of measuring thermal transport properties may be unreliable or unwieldy when applied to nanostructures. However, a simple, all-electrical technique is available for all samples featuring high-aspect-ratio: the 3ωmethod. Nonetheless, its usual formulation relies on simple analytical results which may break down in real experimental conditions. In this work we clarify these limits and quantify them via adimensional numbers and present a more accurate, numerical solution to the 3ωproblem based on the Finite Element Method (FEM). Finally, we present a comparison of the two methods on experimental datasets from InAsSb nanostructures with different thermal transport properties, to stress the crucial need of a FEM counterpart to 3ωmeasurements in nanostructures with low thermal conductivity.

Surface Nano-Patterning for the Bottom-Up Growth of III-V Semiconductor Nanowire Ordered Arrays

Ordered arrays of vertically aligned semiconductor nanowires are regarded as promising candidates for the realization of all-dielectric metamaterials, artificial electromagnetic materials, whose properties can be engineered to enable new functions and enhanced device performances with respect to naturally existing materials. In this review we account for the recent progresses in substrate nanopatterning methods, strategies and approaches that overall constitute the preliminary step towards the bottom-up growth of arrays of vertically aligned semiconductor nanowires with a controlled location, size and morphology of each nanowire. While we focus specifically on III-V semiconductor nanowires, several concepts, mechanisms and conclusions reported in the manuscript can be invoked and are valid also for different nanowire materials.