Pt/AlGaN/AlN/GaN high electron mobility transistors (HEMT) were fabricated and characterized for hydrogen sensing. Pt and Ti/Al/Ni/Au metals were evaporated to form the Schottky contact and the ohmic contact, respectively. The sensors can be operated in either the field effect transistor (FET) mode or the Schottky diode mode. Current changes and time dependence of the sensors under the FET and ...

We study photocurrent generation in individual suspended carbon nanotube p-n junctions using spectrally resolved scanning photocurrent microscopy. Spatial maps of the photocurrent allow us to determine the length of the p-n junction intrinsic region, as well as the role of the n-type Schottky barrier. We show that reverse-bias operation eliminates complications caused by the n-type Schottky bar...

Carbon nanotube transistors have outstanding potential for electronic detection of biomolecules in solution. The physical mechanism underlying sensing however remains controversial, which hampers full exploitation of these promising nanosensors. Previously suggested mechanisms are electrostatic gating, changes in gate coupling, carrier mobility changes, and Schottky barrier effects. We argue th...

In this study, a model of a Schottky-barrier carbon nanotube fieldeffect transistor (CNT-FET), with ferromagnetic contacts, has been developed. The emphasis is put on analysis of current-voltage characteristics as well as shot (and thermal) noise. The method is based on the tight-binding model and the nonequilibrium Green’s function technique. The calculations show that, at room temperature, th...

In this Letter, we experimentally investigate the impact of gate geometry on forward operation Schottky-gate p-GaN high electron mobility transistors (HEMTs). particular, analyze devices with changing gate-metal/p-GaN junction area and p-GaN/AlGaN/GaN heterostructure in linear regime. These exhibit unique threshold voltage subthreshold swing scaling dependence that is contrast classic field-eff...

Aalto University, P.O. Box 11000, FI-00076 Aalto www.aalto.fi Author Tero Kiuru Name of the doctoral dissertation Characterization, modeling, and design for applications of waveguide impedance tuners and Schottky diodes at millimeter wavelengths Publisher School of Electrical Engineering Unit Department of Radio Science and Engineering Series Aalto University publication series DOCTORAL DISSERT...

We report on the first experimental evidence of a Schottky barrier effect produced by the action of light in an otherwise purely Ohmic contact between a nominally undoped photorefractive titanosillenite Bi12TiO20 crystal and a transparent conductive SnO2 electrode. The photorefractive crystal is sandwiched between two transparent electrodes and a Schottky barrier is built up in the illuminated ...

Among atomically thin two-dimensional (2D) materials, molybdenum disulfide (MoS2) is attracting considerable attention because of its direct bandgap in the 2H-semiconducting phase. On the other hand, a 1T-metallic phase has been revealed, bringing complementary application. Recently, thanks to top-down fabrication using electron beam (EB) irradiation techniques, in-plane 1T-metal/2H-semiconduct...

In this paper we calculate the volumes and energies of formation of Schottky defects in the alkali halides NaCl, NaBr, KC1 and KBr. Both the polarisable point-dipole and a simple shell model are evaluated. The calculation uses a generalised and extended Mott-Littleton approach in conjunction with results derived previously by the lattice statics method of Kanzaki. The polarisable point-dipole m...