Silicon carbide (SiC) is an important wide bandgap semiconductor with many polytypes. 3C-SiC is the only cubic polytype, to be distinguished from the hexagonal polytypes such as 4H-SiC and 6H-SiC. Crystalline 3C-SiC, grown by heteroepitaxy, often contains twin structures, also called anti-phase domains (APDs), that are separated by double positioning boundaries (DPBs). This naturally occurs when growing 3C-SiC, since there are two possible and equally-likely stacking sequences with a relative in-plane rotation of 180 degrees as shown in Figure 1. The challenge faced when imaging these APDs, is that neither optical or scanning electron microscopy provides a clear contrast between the rotated domains, as they are composed of the same material with identical properties. This paper demonstrates high-contrast imaging of such APDs, enabled by channeling of electrons or ions.

Graphene is known for its high carrier mobility and high saturation velocity [1][2][3]. The majority of graphene transistors in the literature-including MOSFETs, barristors, and tunneling FETs-have a gate separated from the channel by a conventional or high-K dielectric layer [4][5][6]. In this paper we demonstrate for the first time a lateral graphene FET gated by a graphene/semiconductor heterojunction. The device consists of a p-type graphene channel and an n-type semiconductor gate. Since no metal/dielectric stacked gate is used, the device is referred to as graphene junction FET (G-JFET). Such a device is of interest as an alternate to G-MOSFETs, or as a back gate for G-MOSFETs with the feature that the device's Dirac voltage (VDirac) can be tuned by the doping density of semiconductor gate.The basic device structure and operating principle of the G-JFET are shown in Fig. 1. As graphene is placed on a semiconductor it forms a Schottky junction [7-9], resulting in a depletion region inside the semiconductor which induces a complementary charge in the graphene. Changing the reverse bias across the graphene/semiconductor junction modulates the depletion region width and hence changes the total amount of charge in graphene. Fig. 2 shows the simulated transfer and J-V characteristics of graphene/n-Si G-JFET with variable depletion width model-based on the assumptions of constant carrier mobility and an ideal Schottky junction. The shifting VDirac with increasing Vds and nonlinear J-V curves are a result of graphene's energy band offset along the channel length.

We report theoretical and experimental studies on the metal-dielectric photonic crystal structure, which is constructed by the self-assembly of metal-coated nanoparticles. The finitedifference time-domain (FDTD) simulations were carried out to predict the width and position of the 3D photonic bandgap. For fabrication, we first prepared gold-embedded silica nanoparticles containing extremely small gold nanoparticles. The core particles are then immersed in a goldcontaining solution in which the gold shells were formed by subsequent reduction. Formation of continuous shells was confirmed by scanning electron microscope (SEM) and the optical response due to the surface plasmons. We also performed self-assembly of both the goldembedded core particles and metal-coated particles. SEM micrographs showed the formation highly ordered structures. The optical reflectance spectra exhibited shifts of the Bragg reflection peak due to the change in refractive index produced by gold nanoparticles.

Analysis of hot-filament CVD (HF-CVD) growth of high quality 3C-SiC on micron-sized 3C-SiC mesas is presented. Two types of growth were observed: 1) a relatively slow growth at about 1μm/hour, and 2) an almost three times faster growth, correlated with the presence of domain boundaries in, or adjacent to, the mesas. Both reveal well-defined crystallographic facets and sharp corners between them. The slower growth has been identified to be surface-nucleation-limited, seemingly defect-free, while the faster growth has been identified as being caused by defect-induced step-flow growth. A growth model is presented, yielding a growth rate of 1.18 μm/h for the defect free {111} and (100) plane and 2.8 μm/h for {110} planes.

In the use of block copolymers as templates for nanolithography, deposition, or etching, substantial time and cost savings can be achieved through the use of algebraic models for block copolymer feature size as a function of both the polymer's molecular weight and the relative concentration of a homopolymer additive. Desired average pore diameters and spacing can be achieved on the first try, using off-the-shelf polymers in a wide range of molecular weights. This allows precise nanoscopic components such as quantum dots to be patterned over large areas rapidly, repeatably, and at very low cost.