Photoconductive mechanism of IR-sensitive iodized PbSe thin films via strong hole-phonon interaction and minority carrier diffusion.

Photoconductive PbSe thin films are highly important for mid-infrared imaging applications. However, the photoconductive mechanism is not well understood so far. Here we provide additional insight on the photoconductivity mechanism using transmission electron microscopy, x-ray photoelectron microscopy, and electrical characterizations.

Growth Kinetics and Atomistic Mechanisms of Native Oxidation of ZrSSe and MoS Crystals.

A thorough understanding of native oxides is essential for designing semiconductor devices. Here, we report a study of the rate and mechanisms of spontaneous oxidation of bulk single crystals of ZrSSe alloys and MoS. ZrSSe alloys oxidize rapidly, and the oxidation rate increases with Se content.

Contacts for Molybdenum Disulfide: Interface Chemistry and Thermal Stability.

In this review on contacts with MoS, we consider reports on both interface chemistry and device characteristics. We show that there is considerable disagreement between reported properties, at least some of which may be explained by variability in the properties of geological MoS. Furthermore, we highlight that while early experiments using photoemission to study the interface behavior of metal-MoS showed a lack of Fermi-level pinning, device measurements repeatedly confirm that the interface is indeed pinned.

Atmospheric and Long-term Aging Effects on the Electrical Properties of Variable Thickness WSe Transistors.

Atmospheric and long-term aging effects on electrical properties of WSe transistors with various thicknesses are examined. Although countless published studies report electrical properties of transition-metal dichalcogenide materials, many are not attentive to testing environment or to age of samples, which we have found significantly impacts results. Our as-fabricated exfoliated WSe pristine devices are predominantly n-type, which is attributed to selenium vacancies.

Probing Interface Defects in Top-Gated MoS Transistors with Impedance Spectroscopy.

The electronic properties of the HfO/MoS interface were investigated using multifrequency capacitance-voltage (C-V) and current-voltage characterization of top-gated MoS metal-oxide-semiconductor field effect transistors (MOSFETs). The analysis was performed on few layer (5-10) MoS MOSFETs fabricated using photolithographic patterning with 13 and 8 nm HfO gate oxide layers formed by atomic layer deposition after in-situ UV-O surface functionalization. The impedance response of the HfO/MoS gate stack indicates the existence of specific defects at the interface, which exhibited either a frequency-dependent distortion similar to conventional Si MOSFETs with unpassivated silicon dangling bonds or a frequency dispersion over the entire voltage range corresponding to depletion of the HfO/MoS surface, consistent with interface traps distributed over a range of energy levels.

Atomically Traceable Nanostructure Fabrication.

Reducing the scale of etched nanostructures below the 10 nm range eventually will require an atomic scale understanding of the entire fabrication process being used in order to maintain exquisite control over both feature size and feature density. Here, we demonstrate a method for tracking atomically resolved and controlled structures from initial template definition through final nanostructure metrology, opening up a pathway for top-down atomic control over nanofabrication. Hydrogen depassivation lithography is the first step of the nanoscale fabrication process followed by selective atomic layer deposition of up to 2.

ZnO films grown by pulsed-laser deposition on soda lime glass substrates for the ultraviolet inactivation of biofilms.

We found that a ZnO film of 2 μm thickness which was laser-deposited at room temperature onto a plain soda lime glass substrate, exhibits notable antibacterial activity against a biofilm of when back-illuminated by a UVA light source with a peak emission wavelength of about 365 nm. X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), UV-visible absorption spectroscopy, Raman spectroscopy and x-ray photoemission spectroscopy (XPS) were used to characterize the ZnO films before and after the interactions with the biofilm and the ultraviolet light, respectively. The as-deposited film was highly textured with the wurtzite (0002) in-plane orientation (-axis perpendicular to ZnO surface) and had a surface rms roughness of 49.