Search

International audience; The first direct Barkhausen noise measurement in a ferroelectric thin film is presented. The Barkhausen noise energy loop is reconstructed from the measured Barkhausen noise and is closely related to the classic ferroelectric P vs E hysteresis loop. Grain boundaries act as a dominant ferroelectric domain wall pinning site in a polycrystalline thin film based on the calculated domain wall jump distance using the Barkhausen noise frequency. The technique is promising for the measurement of ferroelectric switching dynamics, and provides a physical insight for improving application performance.

Undoped and Os-doped SnO2 thin films have been deposited by the sol-gel method. Their electrical properties have been investigated by resistivity and Hall effect measurements in order to understand the role of Os in the electrical transport mechanism. The measurements have been carried out in 100-500 K temperature range both in a vacuum and in air. The experimental results have been analyzed according to the grain-boundary scattering mechanism and they have been used to explain the response toward CH4 of the Os-doped SnO2 thin-film-based gas sensors.

Highly (117)- and (001)-oriented Bi3.25La0.75Ti3O12 (BLT) thin films were fabricated on Pt/TiO2/SiO2/Si(100) substrates by chemical solution deposition under the appropriate baking and crystallization conditions. The (117)-oriented BLT films exhibited higher remanent polarization (2Pr=24 μC/cm2), than did (001)-oriented BLT films, which exhibited only a slight amount of polarization (2Pr=6.6 μC/cm2). The results of fatigue and retention tests revealed that neither film was fatigued up to 1×1010 switching cycles, and the retained charge was unchanged for 1×104 s.

Sharp optical absorption and emission peaks near the band gap (Eg≈3.1 eV) were observed in LaCuOS polycrystalline thin films at room temperature. The absorption peak was able to be detected at temperatures as high as 490 K, and its intensity remarkably increased with decreasing temperature. The spectral position of the absorption peak and its temperature dependence almost agreed with those of the emission peak. It was concluded that the sharp absorption and emission peaks originate from excitons. On the basis of semiquantitative consideration about the excitons, it is suggested that the electronic-structure characteristic of the layered-crystal structure of LaCuOS is responsible for the stability of the excitons. The observation of the exciton absorption and emission at room temperature revealed that LaCuOS is a promising material for optoelectronic applications such as light-emitting devices.

This letter investigates the effect of repeated bending of flexible p-channel low-temperature polycrystalline–silicon thin-film transistors employing an ultra-low-temperature process (

Nonequilibrium molecular dynamics simulations have been employed to develop a mechanistic model for the development of an out‐of‐plane (fiber) texture in polycrystalline thin films. The depositing atoms preferentially sputter film atoms from grains with high surface energies. As the film grows, an atomic shadowing mechanism leads to the lateral growth of the grains with a height advantage—eventually leading to the occlusion of randomly oriented grains.

We report photocarrier time-of-flight measurements of electron drift mobilities for the p-type CuIn1−xGaxSe2 films incorporated in solar cells. The electron mobilities range from 0.02 to 0.05 cm2/Vs and are weakly temperature-dependent from 100–300 K. These values are lower than the range of electron Hall mobilities (2-1100 cm2/Vs) reported for n-type polycrystalline thin films and single crystals. We propose that the electron drift mobilities are properties of disorder-induced mobility edges and discuss how this disorder could increase cell efficiencies.

Although polycrystalline thin films of organic materials are applied for organic field effect transistors, their bulk electrical properties have not been characterized. In this study, we investigated hole transport properties in the polycrystalline thin films of a series of quaterthiophene derivatives by both time-of-flight experiments and field effect measurements. The time-of-flight bulk mobility was almost same or smaller than field effect mobility. Both mobilities showed a similar trend as a function of side chain length. We discussed these results from the view point of the intrinsic nature of quaterthiophenes, which gave a fundamental knowledge of charge transport properties in the organic polycrystalline thin films.

A key objective in the design of recording media for hard disk drives is to tailor the grain size. A fourfold increase in the recording density from the current levels demands that the mean grain diameter be reduced from 7 to about 5.5nm, and distribution to below 15%. Traditional techniques involving dopants can realize small grain sizes but also deteriorate the structural and magnetic properties. In this study, the utility of an extremely thin synthetic nucleation layer in reducing the grain size and distribution of the recording media is demonstrated, with significant implications for other applications too.