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 present a new approach for extended-cavity diode-laser tuning to achieve wide mode-hop-free tuning ranges. By using a multiple piezoactuated grating mount, the cavity length and grating angle in the laser can be adjusted independently, allowing mode-hop-free tuning without the need for a mechanically optimized pivot-point mount. Furthermore, synchronized diode injection-current tuning allows...

This paper describes the development of a heterojunction AlGaAs/GaAs PIN diode as a revolutionary improvement as compared to the homojunction GaAs PIN diode commonly used in microwave systems for commercial and military applications. In a heterojunction device the injected carriers from the junction are confined by the bandgap discontinuity between the AlGaAs/GaAs layers. This confinement effec...

We present the characterization of commercial tunnel diode low-level microwave power detectors at room and cryogenic temperatures. The sensitivity as well as the output voltage noise of the tunnel diodes is measured as functions of the applied microwave power. We highlight strong variations of the diode characteristics when the applied microwave power is higher than a few microwatts. For a diod...

Compared to traditional lasers, diode lasers are generally small, reliable and easy to operate. However, tuning characteristics of many commercially available standard diode lasers are often far from ideal. External Cavity Diode Lasers (ECDL), in which antirefl ection (AR) coated Fabry Perot laser diodes can be utilized, provide an attractive alternative with wavelength tuning ranges of up to 1...

The metal-insulator-semiconductor (MIS) diode is the most useful device in the study of semiconductor surfaces. The current-voltage data of the metal-insulatorsemiconductor Schottky diode are simulated using thermionic emission diffusion equation taking into account the interfacial layer parameters. The calculated current–voltage data are fitted into ideal thermionic emission diffusion equation...

Controlling the propagation properties of the terahertz waves in graphene holds great promise in enabling novel technologies for the convergence of electronics and photonics. A diode is a fundamental electronic device that allows the passage of current in just one direction based on the polarity of the applied voltage. With simultaneous optical and electrical excitations, we experimentally demo...

A chemical active medium on the base of Belousov-Zhabotinsky (BZ) medium was used to design a “chemical diode”. This system, similar to a semiconductor diode, shows unidirectional propagation of chemical pulses and may be possible to be used to construct a massively parallel computational medium. The system of two mesoporous glass plates with ferroin loaded at the surface was covered by BZ solu...

Introduction: The ultimate goal of endodontic treatment is to eliminate the bacterial infection in the root canal system. While mechanical debridement combined with chemical irrigation removes the bulk of microorganisms, residual bacteria are readily detectable in approximately one-half of teeth just prior to obturation. Laser light can be used to destroy bacteria. This in vitro study was perfo...