Visible‐color‐tunable light‐emitting diodes (LEDs) with electroluminescent color that changes continuously from red to blue by adjusting the external electric bias are fabricated using multifacetted GaN nanorods with anisotropically formed 3D InGaN multiple‐quantum wells. Monolithically integrated red, green, and blue LEDs on a single substrate, operating at a fixed drive current, are also demonstrated for inorganic full‐color LED display applications.

We report on the optical and electrical transport properties of single-crystalline silicon carbide nanowires (SiC NWs). The NWs were fabricated by a chemical vapor deposition process, and had diameters of <100nm and lengths of several μm. X-ray diffraction and transmission electron microscopy analysis showed the single-crystalline nature of NWs with a growth direction of ⟨111⟩. Photoluminescence characterization showed blue emission at room temperature. The electrical measurements from a field effect transistor structure on individual NWs showed n-type semiconductor characteristics. The resistivity and estimated electron mobility on the NWs are 2.2×10−2Ωcm for 0V of gate voltage and 15cm2∕(Vs), respectively. Our low-resistivity SiC NWs could be applied to a high-temperature operation sensor and actuator due to its own excellent electrical and optical properties.

Current information technology relies on two independent processes: charge-based information processing (microprocessors) and spin-based data storage (magnetic hard drives). [1±5] The prospect of simultaneously manipulating both charge and spin in a single semiconductor medium is provided by the exciting area of spintronics. Among many others, diluted magnetic semiconductors (DMSs) represent the most promising candidates for such applications. [1±7] Herein we report on the magneto-and optoelectronic properties of single-crystalline diluted magnetic semiconductor nanowires Ga 1±x Mn x N (x = 0.01±0.09). These nanowires, which have diameters of 10±100 nm and lengths of up to tens of micrometers, exhibit ferromagnetism with Curie temperatures (T C s) above 300 K and magnetoresistances (MRs) up to 250 K. Spin-dependent electron transport from single-nanowire transistors indicates the homogeneous nature of the ferromagnetic nanowires.Gate-dependent conductance and electroluminescence (EL) from nanowire-based light-emitting-diode structures suggest their p-type characteristics, which might support the theory of hole-mediated ferromagnetism. These ferromagnetic GaN:Mn nanowires represent an important class of nanometer-scale building blocks for spintronics.Theoretical studies indicate that transition-metal-doped GaN possesses a ferromagnetic transition temperature higher than room temperature due to hole-mediated ferromagnetism, [8] which would be advantageous for many of the proposed spintronic applications. Many experiments have already been carried out to demonstrate such hypotheses, [9±11] although significant controversy exists over the possibility of magneticimpurity phase separation in many of these thin-film studies. [12±16] Moreover, intrinsic defects in these films originating from the molecular-beam epitaxial growth process may be the Achilles' heel in reaching a fundamental understanding of the ferromagnetism in these materials. On the other hand, the miniaturization of electronic devices represents an ongoing trend for both industrial manufacture and academic research. Among many other possibilities, nanotubes and nanowires are currently being actively explored as possible building blocks for electronic devices with features smaller than 100 nm. [17] The controlled fabrication and fundamental understanding of low-dimensional ferromagnetic semiconductor nanostructures is thus crucial to the development of semiconductorbased spintronic devices and spin-based quantum-computation schemes.Although progress has been made in the understanding of DMS quantum wells and dots, [1±7] studies of quantum wires are still at a nascent stage. Dimensionality and size are known to play a significant role in determining various properties of the systems. [17] In this regard, a one-dimensional (1D) DMS system at the nanometer scale, i.e., a DMS nanowire, is expected to have interesting magnetoelectronic properties and could be a good candidate for realizing spintronic devices for several reasons. First, nanowires themselve...

We report on a simple and effective ac and dc dielectrophoresis (DEP) method that can be used to align and manipulate semiconductor gallium nitride (GaN) nanowires (NWs) with variations in the type of electrical fields as well as variations of frequency. We observed that the ability of the alignment and the formation of the assembling nanowires (single or a bundle configuration) strongly depend on the magnitude of both the ac and dc electric fields. The yield results indicate that the GaN NWs, using ac DEP, are better aligned with a higher yield rate of approximately 80% over the entire array in the chip than by using dc DEP. In addition, we first demonstrated the simple hybrid p-n junction structures assembled by n-type GaN nanowires together with a p-type silicon substrate (n-GaN NW/p-Si substrate) using dielectrophoresis. From the transport measurements, the p-n junction structures show well-defined current rectifying behaviour with a low reverse leakage current of approximately 3 x 10(-4) A at -25 V. We believe that our unique p-n junction structures can be useful for electronic and optoelectronic nanodevices such as rectifiers and UV nano-LEDs.