High frequency pN heterojunction diodes with cutoff frequencies over 1 THz have been fabricated using narrow bandgap high-mobility semiconductors. The pN heterojunction is composed of a 30 nm thick p-type In0.27Ga0.73Sb alloy and a 130 nm thick In0.69Al0.31As0.41Sb0.59 n-layer. A high-mobility n-type InAs0.66Sb0.34 contact layer is used to connect the mesa diode to a metal Ohmic contact. These ...

The modulation depth of two-dimensional electron-gas (2DEG) based terahertz (THz) modulators using AlGaAs/GaAs hetero-structures with metal gates is inherently limited to <30%. The metal gate not only attenuates the THz signal but also severely degrades modulation depth. Metal losses can be significantly reduced employing an alternative material with tunable conductivity. Graphene presents a un...

In situ studies of the superconducting and normal-state transport properties in partially oxygen-depleted, metallic YBa2Cu3Ox (Tc ,mid'52 K) thin films exposed to long-term white-light illumination ~photodoping! are reported. We observed that the effects of photoexcitation strongly depended on the temperature at which the photodoping was performed. The Hall number increased during the illuminat...

The architecture, size and density of metal oxide field effect transistors (MOSFETs) as unit bricks in integrated circuits (ICs) have constantly changed during the past five decades. The driving force for such scientific and technological development is to reduce the production price, power consumption and faster carrier transport in the transistor channel. Therefore, many challenges and diffic...

Thermodynamic phase diagrams of alloys are usually computed or experimentally determined under the assumption of perfect crystallinity of the material. Here, we show that dislocations can change the phase stability of alloys and increase the size of the miscibility gap. This dislocation-induced destabilization of the alloy originates from an interaction between the elastic fields of the disloca...

We investigated the electron transport properties of n-GaN under an Ohmic-metal. Hall measurement results were compared for (A) before Ti-based metal deposition, (B) after deposition but annealing, (C) Ohmic and (D) Ohmic-metal removal, where multi-probe-Hall device measurements are required (C), while others, (A), (B), (D), can be characterized by conventional measurements. The elucidated that...

The objective of the present study was to investigate the reduction of mobility, availability and toxicity found in soil contaminated with lead (Pb) and cadmium (Cd) from Santo Amaro Municipality, Bahia, Brazil using two combined methods, commonly tested separately according to the literature: metal mobilization with phosphates and phytoextraction. The strategy applied was the treatment with tw...