Tyndall National Institute

About: Tyndall National Institute is a based out in . It is known for research contribution in the topics: Laser & Semiconductor laser theory. The organization has 1473 authors who have published 3607 publications receiving 71911 citations.

Coexistence of negative and positive photoconductivity in few-layer PtSe2 field-effect transistors

Abstract: Platinum diselenide (PtSe_2) field-effect transistors with ultrathin channel regions exhibit p-type electrical conductivity that is sensitive to temperature and environmental pressure. Exposure to a supercontinuum white light source reveals that positive and negative photoconductivity coexists in the same device. The dominance of one type of photoconductivity over the other is controlled by environmental pressure. Indeed, positive photoconductivity observed in high vacuum converts to negative photoconductivity when the pressure is rised. Density functional theory calculations confirm that physisorbed oxygen molecules on the PtSe_2 surface act as acceptors. The desorption of oxygen molecules from the surface, caused by light irradiation, leads to decreased carrier concentration in the channel conductivity. The understanding of the charge transfer occurring between the physisorbed oxygen molecules and the PtSe_2 film provides an effective route for modulating the density of carriers and the optical properties of the material.

Phase-locked mutually coupled 1.3 μm quantum-dot lasers

Abstract: Fabry-Perot InAs quantum-dot lasers grown on GaAs substrates are mutually coupled with a delay of several nanoseconds. Stable phase-locked output with narrow linewidth is obtained when the frequency detuning between the two lasers is less than 4 GHz. This simple locking scheme could find application in a variety of photonics applications.

Nanotubes of core/shell Cu/Cu2O as anode materials for Li-ion rechargeable batteries

Abstract: A direct electrodeposition technique for Cu nanotube array fabrication and the subsequent conversion of the deposited Cu into Cu 2 O was developed. The Cu 2 O nanotube arrays showed high capacity, cyclability, and rate capability. The cycling performance of the Cu 2 O nanotubes showed a high level of structural integrity with capacity retention even after 94 cycles when cycled at 1C to 3C rates. The enhanced electrochemical performance of the Cu 2 O nanotubes came from a high surface area, electrolyte access, high electrical conductivity of Cu core support, and structural integrity of the oxide shell active material.