The ferroelectricity of (Al1−xScx)N (x = 0–0.34) thin films with various thicknesses was investigated. were prepared at 400 °C on (111)Pt/TiOx/SiO2/(001)Si substrates by the radio frequency dual-source reactive magnetron sputtering method using Al and Sc targets under pure N2 gas or a mixture Ar gases. film deposited showed larger remanent polarization than those + mixture. Ferroelectricity observed for x 0.10–0.34 about 140-nm-thick gas. 0.22 down to 48 nm in thickness from...

Chalcopyrite-type CuInS2-based alloyed fluorescent nanocrystals (NCs), which contain no regulated heavy metal ions, were synthesized by heating an organometallic solution to demonstrate optical property tunability. Introduction of Zn into the CuInS2 system enhanced their photoluminescence (PL) intensity. The resultant particles 3−6 nm; they varied with experimental conditions and discrete colloidally stable. band-gap energy PL wavelength Zn-Cu-In-S (ZCIS) NCs content particle size. Their was...

For this study, Cu–In–S nanocrystals were developed as a low toxic fluorescent. The stoichiometric CuInS2 synthesized facilely by heating solution of metal complexes and dodecanethiol. fluorescence would be originated from the crystal defect. We intentionally introduced defect in nanocrystal with prospect that intensity increased. structure products was analyzed using Raman spectroscopy other techniques. have many defects without phase separation observed bulk material. Consequently, quantum...

A micro-reactor was utilized for continuous and controlled CdSe nanocrystal preparation. Effects of reaction conditions on optical properties the nanocrystals were investigated; in this current system, rapid exact temperature control beneficial controlling particle diameter reproducible preparation particles; additional effort made towards narrower particle-size distributions.

The aim of this study is to obtain a systematic insight into the scandium (Sc) concentration dependence spontaneous polarization (Psp) in ScxAl1−xN by using first-principles calculations. From calculated results, we observe that structural change from c-axis polarized wurtzite structure nonpolarized layered hexagonal takes place at x = 0.67, and decreases nonlinearly with Sc concentration. Furthermore, calculate polarizations each cation individually find aluminum–nitrogen (Al–N) (PspAlN)...

The temperature dependence of ferroelectric properties was investigated for (Al0.8Sc0.2)N films 9–130 nm thick prepared on (111)Pt/TiOx/SiO2/Si substrates. coercive fields (Ec) these decreased with increasing measurement up to 523 K, irrespective film thickness, thus realizing polarization switching because the applicable maximum electric field is beyond Ec. As a resultant, remanent (Pr) above 100 μC cm−2 ascertained 9 at 373 and 423 which more than 5 times larger those HfO2-based same...

ZnS-coated CdSe composite particles have been continuously synthesized in a microfluidic reactor. By using this system, and ZnS coating can be produced sequence, the particle size layer thickness directly adjusted by residence time. It demonstrated that continuous synthesis microreactor was simple efficient way to prepare with different structures determine optimized experimental conditions.

Well-dispersed Y2O3:Eu nanocrystals, with a size less than 10 nm, and self-assembled nanodisks (see Figure) could be synthesized by simple organometallic route. Two strong emission peaks located between 610 630 2.6 % quantum yield, are achievable upon excitation at 330 nm. Excellent dispersibility, long lifetime, improved may allow nanocrystals to useful for biological labeling.

An air-stable, low-toxicity, single-molecular source for ZnS is demonstrated to be an appropriate reagent synthesize highly luminescent ZnS-capped CdSe with a narrow size distribution. A photoluminescence quantum yield of above 50 % and peak full width at half maximum around 32 nm could obtained after synthesis using microreactor. The surface the nanocrystals can hydrophilic, while retaining high yield. Microscopic observation shows that accurate time control, which achieved by microreactor,...

A stable interface between two insoluble currents in a microchannel reactor has been obtained by selecting the solvents and adjusting flow rate; titania particles with size of less than 10 nm could be prepared continuously on this interface; new method shows great advantage for control measurement particle sizes.

Aluminum nitride (AlN) is one of piezoelectric materials, which are eagerly anticipated for use in microelectromechanical systems (MEMS) applications such as communication resonators, sensors, and energy harvesters. AlN particularly excellent generated voltage characteristics the MEMS rather than oxide materials lead zirconium titanate Pb(Zr, Ti)O3. However, it necessary to improve properties order advance performance MEMS. We dramatically increased coefficient d33 films by simultaneously...

The effect of pure mechanical strain on ferroelectricity was investigated for (001)-one-axis-oriented (Al0.8Sc0.2)N films deposited (111)Pt-coated substrates with different thermal expansion coefficients. lattice strains were successfully controlled by using coefficients, though the composition is same. changes in remanent polarization (Pr) and coercive field (Ec) values these can be understood internal parameter u representing crystal anisotropy a wurtzite structure. These results suggest...

In this study, the piezoelectric properties of scandium-alloyed gallium nitride (ScGaN), which is expected to be applied microelectromechanical systems devices, are evaluated by first-principles calculations. The constant (d33) GaN found increase up approximately 30 times upon addition 62.5 mol. % Sc. stress (e33) increases and elastic (C33) decreases with increasing Sc content ScGaN, driving rise d33. improved ScGaN compared those largely attributed softening, thought related transition...

Several microreactors combined with an online detector were used as a combinatorial synthesis system to optimize nanoparticle for rapid and flexible development of nanoparticles meet various needs applications. Three reaction parameters—temperature, time, additive (dodecylamine) concentration—were systematically produce condition sets (five points each, total 125 points). The photoluminescence (PL) wavelength, PL quantum yield (PLQY), full width at half-maximum (PL fwhm), particle size,...

The enhancement mechanism of piezoelectric properties by codoping Mg + X (X = Nb, Ti, Zr, Hf) into aluminum nitride (AlN) was investigated first-principles calculations. Theoretically, the constant (d33) can be increased when elastic (C33) is decreased and stress (e33) increased. All components e33, which consists clamped Born effective charge (Z33), strain sensitivity (du/dε) internal parameter, were improved addition AlN. decrease in C33 increase du/dε that observed X-codoped AlN indicate...

Abstract The ferroelectricity of wurtzite, Sc x Ga 1− N ( = 0.35–0.44), was demonstrated in a metal–ferroelectric–metal capacitor. remanent polarization P r ) obtained from positive-up negative-down measurements high, exceeding 120 μ C cm −2 . coercive field E c 0.44 0.56 approximately 3.6 MV −1 at 300 K, which decreased to 3 473 K. We observed that regardless the host material, concentration governed value and Al N, suggesting switching started wurtzite unit cells containing Sc....

The isothermal shrinkage behavior of 2.9 mol% Y 2 O 3 ‐doped ZrO powders with 0–1 mass% Al was investigated to clarify the effect concentration on initial sintering stage. powder compact measured at constant temperatures in range 950°–1050°C. addition increased densification rate increasing temperature. values apparent activation energy ( nQ ) and frequency‐factor term (β 0 n ), where is order depending diffusion mechanism, were estimated stage by applying a sintering‐rate equation data....

Abstract Polarity is among the critical characteristics that could governs functionality of piezoelectric materials. In this study, polarity aluminum nitride (AlN) thin films was inverted from Al-polar to N-polar by doping Si into AlN in range 1–15 at.%. inversion also occurred when MgSi codoped with Mg ratio less than 1. However, can be reversed and greater The effect addition investigated regards their crystal structure, lattice parameters, distribution oxidation state each elements....

The thickness dependences of crystal structures and ferroelectric properties were investigated for (Al0.8Sc0.2)N films with thicknesses 12 to 130 nm deposited on (111)Pt/TiOx/SiO2/(100)Si substrates. internal structural parameter u, representing the anisotropy wurtzite structure, decreased decreasing film thickness. This was attributable mainly in-plane compressive strain originating from larger atomic distance compared that underlying Pt layer. Well-saturated Pr values obtained at room...

The synthesis of nanomaterials is extremely sensitive to various factors under experimental conditions. Therefore, for controlling synthesis, it important ascertain comprehensively the relations between conditions and nanomaterial properties. This study intended acquire in data sets from combinatorial syntheses by means an artificial neural network-based method toward property optimization. Recently, 3404 were obtained systematically using microreactor-based CdSe nanoparticle (NP) examining...

It is recently found that wurtzite aluminum nitride exhibits ferroelectricity by alloying with scandium. Because its remanent polarization (Pr) large, ScxAl1−xN has attracted much attention. Gallium similar structure and properties also expected to show ferroelectricity. Herein, ScxGa1−xN was prepared on a silicon substrate at 673 K using the sputtering method, investigated. Sc0.41Ga0.59N exhibited before dielectric breakdown. Pr of this film, as evaluated via positive-up-negative-down...