Honglei Ma

Thickness dependence of structural, optical and electrical properties of ZnO:Al films prepared on flexible substrates

The thickness dependence of structural, optical and electrical properties of the ZnO:Al films on polypropylene adipate (PPA) substrates have been studied. It was observed that with an increase in film thickness, the crystallite sizes and the density of the films were increased, the resistivity was decreased, and the average transmittance in the wavelength range of the visible spectrum was also slightly decreased.

Preparation and characterization of ITO films deposited on polyimide by reactive evaporation at low temperature

Abstract Sn-doped indium oxide (ITO) films have been prepared on polyimide (PI) thin film substrate at low substrate temperature (80–240°C) by reactive evaporation. The samples were deposited as polycrystalline films with a cubic bixbyite structure and a preferred orientation with the (111) plan parallel to the substrate. The structural, optical and electrical properties of the obtained films depending on deposition temperature have been investigated. High quality films with resistivity as low as 7×10 −4 Ω cm and transmittance over 80% have been obtained by suitably controlling the deposition parameters.

Structural properties and photoluminescence of zinc nitride nanowires

Zinc nitride nanowires can be synthesized by nitridation reaction of zinc powder with ammonia gas in 500ml∕min at the nitridation temperature of 600 °C for 120 min. Studies by using x-ray diffraction indicate that zinc nitride nanowires are cubic in structure with the lattice constant a=0.9788nm. Observations by using scanning electron microscopy, transmission electron microscopy, and high-resolution transmission electron microscopy show that zinc nitride is of nanowire structure. Typical room temperature photoluminescence spectrum of zinc nitride nanowires exhibits an ultraviolet emission peak at 385 nm (3.22 eV) and a blue emission band centered at 450 nm (2.76 eV).

Preparation and properties of indium tin oxide films deposited on polyester substrates by reactive evaporation

Abstract Highly transparent conducting indium tin oxide (ITO) films have been prepared on polyester thin film substrate by reactively evaporating metal In-Sn alloy in a system with an oxygen partial pressure of (3−30) × 10 −5 Torr and substrate temperatures between 80 and 240°C. The structure and opto-electrical properties of the films depending on the deposition conditions have been investigated. High quality films with a average transparency of 83% and the resistivity of 7 × 10 −4 Ω cm have been obtained by controlling the deposition parameters.

Bias voltage dependence of properties for ZnO:Al films deposited on flexible substrate

Abstract Highly transparent conducting Al-doped zinc oxide (ZnO:Al) films with good adherence were deposited on water-cooled polypropylene adipate (PPA) substrate using bias r.f. magnetron sputtering. Films with resistivities as low as 4.6×10 −4 Ω cm and transmittance over 80% have been obtained by adjusting the negative bias voltage of the substrate. The dependence of the structural, electrical and optical properties of these films on the substrate bias voltage was studied in detail.

Comparison of the properties for ZnO:Al films deposited on polyimide and glass substrates

Transparent conducting aluminum–doped zinc oxide (ZnO:Al) films have been prepared on polyimide (PI) and Corning 7059 substrates by r.f. magnetron sputtering technique at low substrate temperature (25–210 °C). Polycrystalline ZnO:Al films having a preferred orientation with the c-axis perpendicular to the substrate were deposited with resistivity as low as 8.5 × 10 −4 cm on PI substrates and 7.1 ×10 − 4 cm on glass substrates. The average transmittance exceeded 74 and 85% in the visible spectrum for 360 and 390 nm thick films deposited on PI and glass, respectively. A comparison of the properties of the films deposited on glass and organic substrates was performed.

ITO films deposited on water-cooled flexible substrate by bias RF Magnetron Sputtering

Abstract 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.%.

Optical and Electrical Properties of Sn-doped Indium Oxide Films Deposited on Polyester by Reactive Evaporation

Transparent conducting Sn-doped indium oxide (ITO) films have been prepared on polyimide (PI) thin film substrate at low substrate temperature by reactive evaporation. The structural, optical and electrical properties of the deposited films have been investigated. High quality films with resistivity as low as 7×10-4 Ωcm and transmittance over 80% have been obtained. The temperature dependence of mobility and carrier concentration have been measured over a temperature range 10–400 K. Corresponding scattering mechanism of charge carriers in the films have been discussed.

Preparation and properties of GaN nanostructures by post-nitridation technique

Abstract Nanostructure GaN films were prepared by post-nitridation technique. The morphology and structure of GaN nanowires are investigated by using transmission electron microscopy and scanning electron microscopy. The growth mechanism of the GaN nanowires is unlikely to be controlled by the well-known vapor–liquid–solid mechanism, vapor–solid phase was involved in the growth of GaN nanostructures. A strong blue photoluminescence is observed for room temperature measurement.

Photoluminescence of SnO2 Films Prepared by APCVD

SnO2 films were prepared by atmosphere pressure chemical vapor deposition (APCVD) method. The preparation, structure and photoluminescence (PL) properties of the SnO2 films were investigated. All the obtained films were polycrystalline with the rutile structure. A violet (396 nm) and a blue (446 nm) photoluminescence peaks were observed at room temperatures. The intensity of the PL peaks located at 3.13 eV decreased with increasing the annealing temperature. The emission mechanism of the SnO2 films has been investigated.