Search results for "Reflectivity"

Effect of ion irradiation on the stability of amorphous Ge2Sb2Te5 thin films

2008

The archival life of phase-change memories (PCM) is determined by the thermal stability of amorphous phase in a crystalline matrix. In this paper, we report the effect of ion beam irradiation on the crystallization kinetics of amorphous Ge2Sb2Te5 alloy (GST). The transition rate of amorphous GST films was measured by in situ time resolved reflectivity (TRR). The amorphous to crystal transformation time decreases considerably in irradiated amorphous GST samples when ion fluence increases. The stability of amorphous Ge2Sb2Te5 thin films subjected to ion irradiation is discussed in terms of the free energy variation of the amorphous state because of damage accumulation. © 2008 Elsevier B.V. Al…

Characterization of ALD grown Ti x Al y N and Ti x Al y C thin films

2017

Abstract Atomic layer deposition (ALD) was used to grow Ti x Al y N and Ti x Al y C thin films using trimethylaluminum (TMA), titanium tetrachloride and ammonia as precursors. Deposition temperature was varied between 325 °C and 500 °C. Films were also annealed in vacuum and N 2 -atmosphere at 600–1000 °C. Wide range of characterization methods was used including time-of-flight elastic recoil detection analysis (ToF-ERDA), X-ray diffractometry (XRD), X-ray reflectometry (XRR), Raman spectroscopy, ellipsometry, helium ion microscopy (HIM), atomic force microscopy (AFM) and 4-point probe measurement for resistivity. Deposited films were roughly 100 nm thick and contained mainly desired elemen…

Coating and functionalization of high density ion track structures by atomic layer deposition

2016

In this study flexible TiO 2 coated porous Kapton membranes are presented having electron multiplication properties. 800 nm crossing pores were fabricated into 50  m thick Kapton membranes using ion track technology and chemical etching. Consecutively, 50 nm TiO 2 films were deposited i nto the pores of the Kapton membranes by atomic layer deposition using Ti( i OPr) 4 and water as precursors at 250 °C. The TiO 2 films and coated membranes were studied by scanning electro n microscopy (SEM), X - ray diffraction (XRD) and X - ray reflectometry (XRR). Au metal electrod e fabrication onto both sides of the coated foils was achieved by electron beam evaporation. The electron multipliers were o…

(1,3,4‐Oxadiazole)copper(II) Compounds: Dimensionality, Magnetism and Nuclease Activity

2009

The work presented here describes the synthesis of new copper(II) complexes derived from 2-amino-5-(pyridin-2-yl)-1,3,4-oxadiazole (L1) and 2-methylamino-5-(pyridin-2-yl)-1,3,4-oxadiazole (L2) which also incorporate azido (N3 -), thiocyanato (NCS-), cyanato (NCO-), dicyanamido [N(CN)2 -, dca] and malonato (C3H2O4 2-, mal) coligands. Structures of the [Cu(L2)(mal)(H2O)]·2H 2O(1), [{Cu(L2)(mal)}2] (2), [Cu(L 2)2-(NCS)2] (3), [Cu(L1)(NCS) 2]n (4) and [{Cu(L2)}2(dca) 2](ClO4)2·2H2O (5) compounds show the dependence of the dimensionality on parameters such as the type of oxadiazole and coligand utilised, solvents or reaction times. In this sense, 1 and 3 are mononuclear complexes, 2 contains cen…

Uniform fibre Bragg gratings with an embedded perturbed section for multiple applications

1999

The interest in fibre Bragg gratings has been increased with the development of flexible fabrication techniques which are able to make gratings with any non-uniform characteristic (chirped, apodised, sampled, phase-shifted, etc.) required for an specific application [1].

Reflectance mode confocal microscopy and digital image analysis in naevus of Hori and pathogenetic evaluation

2012

Hyperspectral imaging reveals spectral differences and can distinguish malignant melanoma from pigmented basal cell carcinomas : A pilot study

2021

Pigmented basal cell carcinomas can be difficult to distinguish from melanocytic tumours. Hyperspectral imaging is a non-invasive imaging technique that measures the reflectance spectra of skin in vivo. The aim of this prospective pilot study was to use a convolutional neural network classifier in hyperspectral images for differential diagnosis between pigmented basal cell carcinomas and melanoma. A total of 26 pigmented lesions (10 pigmented basal cell carcinomas, 12 melanomas in situ, 4 invasive melanomas) were imaged with hyperspectral imaging and excised for histopathological diagnosis. For 2-class classifier (melanocytic tumours vs pigmented basal cell carcinomas) using the majority of…

Kinetic behaviour of a structural phase transition in Langmuir-Blodgett multilayers studied by energy dispersive x-ray reflectivity

1992

Various multilayers of Cd stearate were prepared by means of the Langmuir-Blodgett technique and investigated at T = Ts - ΔT (Ts, melting point of LB film). The x-ray scattering spectrum was recorded in several time intervals using an energy dispersive set up. For ΔT = 3 ... 9 K the observed intensity reduction of Bragg peaks, which corresponds to the multilayer periodicity, is recorded as a function of time. In addition new peaks appear. This is interpreted in terms of a kinetically driven phase separation of the metastable LB-phase. The time needed for phase disorder and the nucleation of the new phase decreases for smaller ΔT. The measured layer spacing of the new phase is larger than th…

Study on Structural, Mechanical, and Optical Properties of Al2O3–TiO2 Nanolaminates Prepared by Atomic Layer Deposition

2015

Structural, optical, and mechanical properties of Al2O3/TiO2 nanolaminates fabricated by atomic layer deposition (ALD) were investigated. We performed transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray reflectivity (XRR), energy dispersive X-ray spectroscopy (EDX), ellipsometry, UV–vis spectroscopy, photoluminescence (PL) spectroscopy, and nanointendation to characterize the Al2O3/TiO2 nanolaminates. The main structural, optical, and mechanical parameters of Al2O3/TiO2 nanolaminates (thickness, grain size, refractive index, extinction coefficient, band gap, hardness, and Young’s module) were calculated. It was established that with decreasing of the layer thickness, the …

Structural and optical properties of TiO2–Al2O3nanolaminates produced by atomic layer deposition

2015

Structural and optical properties of Al2O3/TiO2 nanolaminates fabricated by atomic layer deposition (ALD) were investigated. We performed Raman spectroscopy, transmission electron microscopy (TEM), X-Ray reflectivity (XRR), UV-Vis spectroscopy, and photoluminescence (PL) spectroscopy to characterize the Al2O3/TiO2 nanolaminates. The main structural and optical parameters of Al2O3/TiO2 nanolaminates were calculated. It was established that with decreasing of the layer thickness, the value of band gap energy increases due to the quantum size effect related to the reduction of the nanograins size. It was also shown that there is an interdiffusion layer at the Al2O3/TiO2 interface which plays a…