Search

The origination of ill-defined layer in organic spin valves was investigated by using atomic force microscopy (AFM) and Rutherford backscattering (RBS) analysis. It was found that conductive bulges of LSMO film and self-grown pinholes in Alq3 film other than Co inclusions could lead to the formation of ill-defined layer. The morphology of LSMO substrate had a strong influence on that of Alq3 film, LSMO/Alq3 and Alq3/Co interfaces. Moreover, Alq3 film with the thickness of 1–4 nm could be barriers which was explained by small active area and added insulated layer in organic magnetic tunnel junctions.

A new transparent conducting oxide (TCO) film with low resistivity and high transmittance in the visible range, molybdenum-doped zinc oxide (MZO), was successfully prepared by RF magnetron sputtering method on glass substrates at room temperature. The structural, electrical, and optical properties as a function of film thickness were investigated. All the samples have a preferred orientation with the (0 0 2) planes parallel to the substrates. The resistivity initially decreases and then shows an increase with the increase of the film thickness. When the thickness is 400 nm, the film has its best crystallinity and lowest resistivity 9.2 × 10 −4 Ω cm with a Hall mobility of 30 cm 2 V −1 s −1 and a carrier concentration of 2.3 × 10 20 cm −3 . The average transmittance in the visible range exceeds 84% for all thickness films.

Indium tin oxide (ITO) films were deposited on water-cooled polypropylene adipate (PPA) substrate using bias RF magnetron sputtering from a ceramic target composed of In 2 O 3 (90%)+SnO 2 (10%). Good polycrystalline-structured ITO films with a low electrical resistivity of 6.3×10 −4 Ω cm have been obtained by applying a negative bias of about −40 V to the substrate at a water-cooled substrate temperature (18±2°C). The visible transmittance of all obtained films was over 80% and in the wavelength range of 400–550 nm, the transmittances increase with increasing the negative bias. X-ray diffraction spectra revealed that all the films oriented preferably with [222] direction and [400] diffraction peak decreased with increasing the negative bias. Both the X-ray diffraction spectra and atomic force microscope (AFM) measurement suggested that the average crystalline size, as well as the conductivity have a maximum value at the bias of about −40 V. The influences of argon pressure and the proportion of SnO 2 on the conductivity of the films were also studied. The optimum argon pressure is 0.5–1 Pa, and the proper content of SnO 2 is 7.5–10 wt.%.