Search results for "semiconductor"
showing 10 items of 974 documents
Physical Fundamentals of Biomaterials Surface Electrical Functionalization
2020
This article is focusing on electrical functionalization of biomaterial&rsquo
Water-dispersed semiconductor nanoplatelets with high fluorescence brightness, chemical and colloidal stability
2019
Quasi-two dimensional semiconductor nanoplatelets (NPLs) exhibit high spectral brightness and large absorption cross sections, making them promising for various applications including bioimaging. However, the synthesis of NPLs takes place in organic solvents, therefore they require phase transfer in order to use them in aqueous environments. The phase transfer of NPLs has so far been challenging with few examples in literature. This is likely due to the facile agglomeration of materials with plate-like geometries during the coating procedure. Here we demonstrate how to overcome agglomeration and transfer NPLs, individually coated with amphiphilic polymer chains, to aqueous phase. Upon one a…
Tunability of Injection Seeded High-Repetition Rate Ti:Sapphire Laser Far Off the Gain Peak
2009
We have investigated a tunability of a high‐repetition rate Ti:Sapphire laser seeded off the gain peak. By applying a birefringent filter, the 7 kHz injection seeded Ti:Sapphire laser system was operated with the average seeding efficiency of over 90% and the output power of over 1 W on the spectral range of 900–930 nm. We conclude that the birefringent filter suited for widely tunable operation of the injection seeded Ti:Sapphire laser system operated at high repetition rate.
Polymeric carbon nitride (C3N4) as heterogeneous photocatalyst for selective oxidation of alcohols to aldehydes
2018
Abstract Polymeric carbon nitride (C3N4) is a semiconductor material which is a very promising green photocatalyst with good physico-chemical properties and stability. It is a metal-free carbon based non-toxic material which can be easily obtained from earth-abundant components. The robustness and versatility of C3N4 as a photo-redox catalyst allows its use for selective oxidations by heterogeneous photocatalysis. This paper reviews the state of art in the application of C3N4 as heterogeneous photocatalyst for selective oxidation of alcohols to the corresponding aldehydes.
Effect of alloying elements on the electronic properties of thin passive films formed on carbon steel, ferritic and austenitic stainless steels in a …
2014
The influence of alloying elements on the electrochemical and semiconducting properties of thin passive films formed on several steels (carbon steel, ferritic and austenitic stainless steels) has been studied in a highly concentrated lithium bromide (LiBr) solution at 25 °C, by means of potentiodynamic tests and Mott Schottky analysis. The addition of Cr to carbon steel promoted the formation of a p-type semiconducting region in the passive film. A high Ni contentmodified the electronic behaviour of highly alloyed austenitic stainless steels.Mo did notmodify the electronic structure of the passive films, but reduced the concentration of defects.
Application of amorphous chalcogenide thin films in optical recording technologies
2005
A solid immersion holographic method for the recording of refractive-index and surface-relief modulated gratings with a period of 0.2 µm–1 µm in amorphous films of chalcogenide semiconductors As2S3 and As-S-Se has been developed and studied. The angular selectivity of holographic recording in amorphous chalcogenide thin films can be improved significantly by a decrease of grating period. The possibility to use the amorphous chalcogenide films as a media for holographic recording and storage of information with high density is discussed. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Thickness identification of atomically thin InSe nanoflakes on SiO2/Si substrates by optical contrast analysis
2015
Abstract Single layers of chalcogenide semiconductors have demonstrated to exhibit tunable properties that can be exploited for new field-effect transistors and photonic devices. Among these semiconductors, indium selenide (InSe) is attractive for applications due to its direct bandgap in the near infrared, controllable p- and n-type doping and high chemical stability. For its fundamental study and the development of practical applications, rapid and accurate identification methods of atomically thin nanosheets are essential. Here, we employ a transfer matrix approach to numerically calculate the optical contrast between thin InSe flakes and commonly used SiO2/Si substrates, which nicely re…
Efficient wide band gap double cation – double halide perovskite solar cells
2017
In this work we study the band gap variation and properties of the perovskite compound Cs0.15FA0.85Pb(BrxI1−x)3 as a function of the halide composition, with the aim of developing an efficient complementary absorber for MAPbI3 in all-perovskite tandem devices. We have found the perovskite stoichiometry Cs0.15FA0.85Pb(Br0.7I0.3)3 to be a promising candidate, thanks to its band gap of approximately 2 eV. Single junction devices using this perovskite absorber lead to a maximum PCE of 11.5%, among the highest reported for solar cells using perovskites with a band gap wider than 1.8 eV.
Optical and magnetic properties of ZnCoO thin films synthesized by electrodeposition
2008
Ternary Zn1−xCoxO crystalline films with different compositions were grown by electrodeposition. The Co content in the final compound is linked to the initial Co/Zn ratio in the starting solution. X-ray diffraction reveals a wurtzite structure for the Zn1−xCoxO films. Transmittance spectra show two effects proportional to Co content, a redshift of the absorption edge and three absorption bands, which are both interpreted to be due to the Co incorporated into the ZnO lattice. The amount of deposited charge was used to get a precise control of the film thickness. Magnetic measurements point out that Co(II) ions are isolated from each other, and consequently the films are paramagnetic. Francis…
Spin polarized tunneling at room temperature in a Heusler compound-a non-oxide material with a large negative magnetoresistance effect in low magneti…
2003
Summary form only given. Materials which display large changes in resistivity in response to an applied magnetic field (magnetoresistance) are currently of great interest due to their potential for applications in magnetic sensors, magnetic random access memories, and spintronics-a new kind of electronics based on spin instead of charge. Although ferromagnetic manganites show colossal magnetoresistance (CMR) effects around their Curie temperature, the low field and nearly temperature independent magnetoresistance properties important for spintronics are found only at low temperatures. Guided by striking features in the electronic structure of several magnetic compounds, we prepared the Heus…