Nitridation of HfSiO films improves certain physical and electrical properties—when using gate stack layers—such as their crystallization temperature resistance to interdiffusion. We have studied the band alignment HfSiON by soft x-ray photoemission, oxygen K-edge absorption, spectroscopic ellipsometry. reduced gap 1.50eV±0.05eV, valence- conduction-band offsets 1.2eV±0.1eV 0.33eV±0.05eV, respectively. Although band-gap reduction should lead increased leakage, barrier heights are still...

We determined the band alignment of a graphene-insulator-semiconductor structure using internal photoemission spectroscopy. From flatband voltage and Dirac voltage, we infer 4.6× 1011cm−2 negative extrinsic charge present on graphene surface. Also, extract work function to be 4.56 eV, in excellent agreement with theoretical experimental values literature. Electron hole injection from heavily doped p-type silicon (Si) are both observed. The barrier height top valence Si bottom conduction...

We systematically measure the dielectric function of atomically thin MoS2 films with different layer numbers and demonstrate that excitonic effects play a dominant role in when are less than 5-7 layers thick. The shows an anomalous dependence on number. It decreases number increasing thick but turns to increase for thicker films. show this is because effect very strong its contribution may dominate over band structure. also extract value layer-dependent exciton binding energy Bohr radius by...

A self-powered ultraviolet (UV) photodetector (PD) based on p-NiO and n-ZnO was fabricated using low-temperature sputtering technique indium doped tin oxide (ITO) coated plastic polyethylene terephthalate (PET) substrates. The p-n heterojunction showed very fast temporal photoresponse with excellent quantum efficiency of over 63% under UV illumination at an applied reverse bias 1.2 V. engineered ultrathin Ti/Au top metal contacts transparent PET/ITO substrates allowed the PDs to be...

Recently emerging large-area single-layer MoS2 grown by chemical vapor deposition has triggered great interest due to its exciting potential for applications in advanced electronic and optoelectronic devices. Unlike gapless graphene, an intrinsic band gap the visible which crosses over from indirect a direct when reduced single atomic layer. In this article, we report comprehensive study of fundamental optical properties revealed spectroscopy Raman, photoluminescence, vacuum ultraviolet...

The crystallinity of atomic layer deposition hafnium oxide was found to be thickness dependent, with the thinnest films being amorphous and thick at least partially crystalline. Hafnium fabricated by metalorganic chemical vapor are mostly monoclinic. Formation silicate admixture 20% Si prevents crystallization. Electronic defects reflected an absorption feature 0.2–0.3 eV below optical bandgap. These arise in polycrystalline, but not amorphous, hafnium-based oxides.

Abstract We perform high-throughput density functional theory (DFT) calculations for optoelectronic properties (electronic bandgap and frequency dependent dielectric function) using the OptB88vdW (OPT) Tran-Blaha modified Becke Johnson potential (MBJ). This data is distributed publicly through JARVIS-DFT database. used this to evaluate differences between these two formalisms quantify their accuracy, comparing experimental whenever applicable. At present, we have 17,805 OPT 7,358 MBJ...

As high-permittivity dielectrics approach use in metal-oxide-semiconductor field-effect transistor production, an atomic level understanding of their dielectric properties and the capacitance structures made from them is being rigorously pursued. We others have shown that crystal structure ZrO2 films considerable effects on permittivity as well band gap. The as-deposited reported here appear amorphous below a critical thickness (∼5.4nm) transform to predominantly tetragonal phase upon...

Solution-processed high-efficiency p–n heterojunction photodetectors have been developed using transition metal oxides.

The metal gate/high-k dielectric/III-V semiconductor band alignment is one of the most technologically important parameters. We report offsets Al/Al2O3/GaAs structure and effect GaAs surface treatment. energy barrier at Al2O3 sulfur-passivated interface found to be 3.0±0.1 eV whereas for unpassivated or NH4OH-treated 3.6 eV. At Al/Al2O3 interface, all samples yield same height 2.9±0.2 With a gap 6.4±0.05 Al2O3, alignments both interfaces are established.

We report on the significant performance enhancement of SnO2 thin film ultraviolet (UV) photodetectors (PDs) through incorporation CuO/SnO2 p-n nanoscale heterojunctions. The nanoheterojunctions are self-assembled by sputtering Cu clusters that oxidize in ambient to form CuO. attribute improvements enhanced UV absorption, demonstrated both experimentally and using optical simulations, electron transfer facilitated nanoheterojunctions. peak responsivity PDs at a bias 0.2 V improved from 1.9...

Solution-processed p–n heterojunction photodiodes have been fabricated based on transition-metal oxides in which NiO and ternary Zn1–xMgxO (x = 0–0.1) employed as p-type n-type semiconductors, respectively. Composition-related structural, electrical, optical properties are also investigated for all the films. It has observed that bandgap of films can be tuned between 3.24 3.49 eV by increasing Mg content. The highly visible-blind junction show an excellent rectification ratio along with good...

The interface of zirconium oxide thin films on silicon is analyzed in detail for their potential applications the microelectronics. formation an interfacial layer ZrSixOy with graded Zr concentration observed by x-ray photoelectron spectroscopy and secondary ion mass spectrometry analysis. as-deposited ZrO2/ZrSixOy/Si sample thermally stable up to 880 °C, but less compared ZrO2/SiO2/Si samples. Post-deposition annealing oxygen or ammonia improved thermal stability 925 likely due...

We report the optical properties of unannealed hafnium–aluminate (HfAlO) films grown by atomic layer chemical vapor deposition (ALCVD) and correlate them with aluminum contents in films. Vacuum ultraviolet spectroscopic ellipsometry (VUV-SE), high-resolution transmission electron microscopy (HRTEM), channeling Rutherford backscattering spectrometry (RBS), resonant nuclear reaction analysis (NRA) were employed to characterize these In analyses data, a double Tauc–Lorentz dispersion produces...

We demonstrate high frequency switching characteristics of TFETs based on the In <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.9</sub> Ga xmlns:xlink="http://www.w3.org/1999/xlink">0.1</sub> As/GaAs xmlns:xlink="http://www.w3.org/1999/xlink">0.18</sub> Sb xmlns:xlink="http://www.w3.org/1999/xlink">0.82</sub> material system. These near broken-gap (NBTFETs) with 200nm channel length exhibit record drive current (I...

A facile, low-cost, scalable, catalyst-free solution-processed method is used to grow high-quality antimony selenide nanostructures from a molecular ink directly on flexible substrates for high-performance near-infrared photodetectors. The fabricated photodetectors exhibit fast response and high performance with excellent flexibility durability, suggesting strong potential broadband optoelectronic device applications.

A comprehensive analysis of the compositional heterogeneity and carrier dynamics in novel rubidium-doped 3D/2D perovskites is investigated, showing a PCE over 20% improved stability at ≈50% relative humidity without encapsulation.

The existence of both the strain and microroughness at interface thermally grown SiO2 films on Si was ascertained unambiguously for first time by high accuracy spectroscopic ellipsometry. dielectric function determined a comprehensive data analysis procedure. By carefully examining obtained our model, seen to cause red shift 0.042 eV interband critical point E1 compared with bulk silicon value. thickness region found be 2.2 nm which significant part is due strain.

Spectroscopic ellipsometry was used to determine the real and imaginary parts of dielectric function ZnSe thin films grown on (001) GaAs substrates by molecular-beam epitaxy, for energies between 1.5 5.0 eV. A sum harmonic oscillators is fit in order values threshold at critical points. The fundamental energy gap determined be 2.68 E0+Δ0 E1 points were found equal 3.126 4.75 eV, respectively. Below absorption edge, a Sellmeir-type represent refractive index. At points, E0 E0+Δ0, fitting...

Transition-metal dichalcogenides (TMDCs) have offered experimental access to quantum confinement in one dimension. In recent years, metallic TMDCs like ${\mathrm{NbSe}}_{2}$ taken center stage with many of them exhibiting interesting temperature-dependent properties such as charge density waves and superconductivity. this paper, we perform a comprehensive optical analysis by utilizing Raman spectroscopy, differential reflectance contrast, spectroscopic ellipsometry. These analyses, when...

We have measured x-ray absorption spectra (XAS) at the oxygen K edge for hafnium oxide (HfO2) films grown by chemical vapor deposition (CVD) and atomic layer (ALD), as well silicate (HfSiO) CVD. The XAS results are compared to diffraction (XRD) spectroscopic ellipsometry (SE) data from same films. Features characteristic of crystalline HfO2 observed in all CVD-grown films, even a thickness 5 nm where XRD is not sensitive. ALD-grown exhibit signature crystallinity only that 20 or thicker....

This study attempts a new approach using Moderate Resolution Imaging Spectroradiometer (MODIS) time-series imagery to evaluate the agro-ecological interpretation of rice-cropping systems in flood-prone areas. A series wavelet-based methodologies were applied reveal dynamic relationships among annual flood inundation, rice phenology, and land-use change Vietnamese Mekong Delta (VMD). The rice-heading dates multicropping areas estimated by detecting local maximal points smoothed Enhanced...