The Schottky-barrier static induction transistor (SIT) does not require any p-type materials and gate dielectrics for its operation, providing a straightforward way to develop GaN-based high-frequency power devices. The first derivative of output curves of a Schottky-junction vertical channel GaN SIT with sub-micrometer-sized fin was studied by Jaeyi Chun et al. at Stanford WBG-Lab (article number 1900545) to understand its fundamental electrical properties. The derivative of output curves increases as a function of drain voltage in ohmic region due to the raised potential minima in the channel, which has not been seen in SITs with relatively long fin width.

Anomalous carrier transport properties in turbostratic multilayer graphene have been studied by Ryota Negishi et al. in article number 1900437. The conductance and carrier mobility in the synthesized turbostratic multilayer graphene are higher than those of the monolayer graphene used as growth template. The enhancement is caused by a screening effect in multistacking and by a turbostratic stacking effect where the band structure of the multilayer graphene is similar to that of the monolayer graphene.

ZnO films grown by atomic layer deposition between 100 and 200 °C show strong correlation between growth temperature and conductivity. The films grown at 100 °C are oxygen-rich, show considerably more intensive acceptor photoluminescence and a few times longer photoluminescence decay time than films deposited at 200 °C. They can be converted to p-type when they are doped with N and annealed.

The chemical vapor deposition for the growth of BN thin films on Al₂O₃ substrates using B₂H₆ and NH₃ is investigated. Hexagonal BN films with honeycomb-like wrinkle patterns are observed. The BN film shows a Raman shift at 1369 cm⁻¹ with a full width at half maximum of 20 cm⁻¹, corresponding to the first-order E_2g symmetry vibrational mode in h-BN.

The Hall-effect measurement data on n-InP samples reported in the literature are analyzed on the basis of an impurity-Hubbard-band model to show the significant effects of the top Hubbard band (D⁻ band) on the Hall coefficient and the Hall mobility. The reliable values of the activation energy of hopping Hall mobility in the top Hubbard band are deduced.

The effects of strong-acid treatment on an epitaxial graphene film on a SiC substrate are investigated to confirm compatibility with conventional semiconductor device fabrication processes. An epitaxial graphene film is treated with a piranha solution (H₂O₂ + H₂SO₄) for five times. Raman spectroscopy shows almost constant before and after treatment, indicating its quite high stability.

n-Doped InGaP:Si nanowire shells in coaxial GaAs/InGaP core–shell and core–multishell nanowires are analyzed regarding donor concentration, ohmic contacts, as well as their implementation as electron-supplying emitter shells in a nanowire heterojunction bipolar transistor. Multi-tip scanning tunneling microscopy, current–voltage and electroluminescence measurements are used for the material characterization and the analysis of carrier transport mechanisms.

N-doped Cu₄O₃ thin films are deposited by radio frequency sputtering in an ambient of Ar, O₂ and N₂. Undoped and N-doped Cu₄O₃ films show a direct forbidden transition at E_g = 1.34–1.44 eV. All Cu₄O₃ films show p-type conductivity. N-doped Cu₄O₃ shows lower resistivity on the order of 10¹–10² Ω cm. N-doped Cu₄O₃ is a very promising material in low-cost photovoltaics.

The dependence of the electrical properties of Mg-ion-implanted GaN on the dosage is investigated using metal-oxide-semiconductor diodes. The frequency dispersion in the capacitance–voltage characteristics becomes severe and persistent by increasing the dosage, which is found to result from a discrete interface trap, at 0.2–0.3 eV below the conduction band, generated in GaN by Mg-ion implantation.

Herein, the influence of Ga–OH bonds at the SiO₂/GaN interface is investigated. The Ga–OH bonds establish negative charges and behave as electron traps. The negative influences of the Ga–OH-related traps are reduced by low-temperature annealing.

The low-frequency noise of GaN p–n junctions grown on GaN substrates is characterized. The forward bias noise spectra are predominantly 1/f, whereas in reverse bias the devices exhibit white noise in avalanche. The excess noise factor F and impact ionization ratio α/β are extracted from the noise; F < 1 is obtained, indicating the promise of GaN-based devices for low-noise applications.

Morphology evolution of InSb/InAs quantum nanostripes (QNSs) grown by molecular beam epitaxy with respect to the number of InSb monolayers is investigated. The dominant lateral growth is explained by the difference in surface energy along each direction, which corresponds to different atomic arrangements in the crystalline structure of InSb. The shrinkage of embedded QNSs in the lateral dimension is observed.

The B incorporation into graphitic carbon nitride (g-C₃N₄) films with various compositions through the thermal chemical vapor deposition is investigated. The B incorporation into g-C₃N₄ films is revealed by X-ray photoelectron spectroscopy. The photoluminescence (PL) peak shifts from 2.75 eV for unintentionally doped g-C₃N₄ to 3.60 eV for B-incorporated g-C₃N₄ with a composition of 8.0%.

Single-stranded-DNA-modified graphene field-effect transistors (FETs) detect ethanol gas at the parts per billion (ppb) level and the different DNA sequences cause a difference in ethanol sensing, owing to the change in DNA conformation when gas is adsorbed. Therefore, the devices have considerable potential to detect various gases at a low concentration for practical breath analysis.

The two-wavelength excited photoluminescence (TWEPL) method reveals the presence of nonradiative recombination (NRR) centers in GaPN (N:0.105%). Different contribution of one and two-level models explains the energy dependence of below-gap excitation (BGE). The shift of Fermi-energy in the mid-gap level according to above-gap excitation (AGE) photon number density plays an important role in the interpretation of NRR processes, which must be minimized for improving intermediate band solar cells (IBSCs).

In single self-assembled InAlAs quantum dots, the role of nuclear quadrupole interaction (NQI) in the in-plane nuclear field formation is studied by the Hanle-effect measurements. The origin of NQI and the influence of a longitudinal magnetic field are revealed. The results indicate the multirole of the NQI in the in-plane nuclear field formation.

The photoluminescence of below-bandgap defects from thermally treated semi-insulating GaAs is investigated. Various electronic states that give rise to near-infrared luminescence peaks are generated through thermal treatment at temperatures that are standard for epitaxial growth of InAlGaAs structures on (001) GaAs substrates. The identities of these defects are also proposed.

Herein, the growth of InAs quantum dots (QDs) on a five-step graded InGaAs metamorphic buffer layer (MBL) by molecular beam epitaxy is reported. Anisotropic relaxation along the [−1 1 0] and [1 1 0] directions in the InGaAs MBL is revealed by reciprocal space mapping. Emission at 1.6 μm from the metamorphic InAs QDs is observed at room temperature.

A novel fabrication method for suspended nanowire (NW) mechanical devices is developed, which uses inkjet-printing and trenches filled with PMGI for the precise assembly of suspended NWs. The method enables us to make more complex and more advanced nanoelectromechanical system (NEMS) devices such as quantum structures coupled with nanomechanical systems.

The carrier transport properties of a turbostratic multilayer graphene are evaluated. The values of the conductance and carrier mobility in the multilayer graphene are higher than those of the monolayer graphene. The enhancement of electrical performance is explained by a screening effect of the charged impurities on the device due to the multistacking.

SiO₂ thickness is varied to evaluate the bulk oxide charges and near-interface charges in SiO₂/GaN metal-oxide-semiconductor capacitors. From the analysis, it can be said that the bulk charges have a negative value, and interface charges have a positive value. In addition, it is revealed that the positive charges near the interface are present up to about 25 nm from GaN.

A novel fabrication process of hexagonal aluminum nitride (AlN)/(001) diamond by means of sputtering and high-temperature annealing is proposed. The in-plane epitaxial relationship in AlN/diamond structure is stabilized in the single domain of (0001) [11–20] AlN || (001) [110] diamond on single-crystal diamond substrates with off-cut angle along [110].

The fundamental electrical properties of a Schottky-junction vertical channel GaN static induction transistor, based on the analysis of the first derivative of its output curve, are discussed. The results cover the unique properties of conduction mechanism in a submicrometer channel and the device electrostatics governed by the external biases to control the performance of the device.