Rare Earth Doped Zinc Oxide Research Articles

Enhanced Luminescence of Yb3+ Ions Implanted to ZnO through the Selection of Optimal Implantation and Annealing Conditions

Rare earth-doped zinc oxide (ZnO:RE) systems are attractive for future optoelectronic devices such as phosphors, displays, and LEDs with emission in the visible spectral range, working even in a radiation-intense environment. The technology of these systems is currently under development, opening up new fields of application due to the low-cost production. Ion implantation is a very promising technique to incorporate rare-earth dopants into ZnO. However, the ballistic nature of this process makes the use of annealing essential. The selection of implantation parameters, as well as post-implantation annealing, turns out to be non-trivial because they determine the luminous efficiency of the ZnO:RE system. This paper presents a comprehensive study of the optimal implantation and annealing conditions, ensuring the most efficient luminescence of RE3+ ions in the ZnO matrix. Deep and shallow implantations, implantations performed at high and room temperature with various fluencies, as well as a range of post-RT implantation annealing processes are tested: rapid thermal annealing (minute duration) under different temperatures, times, and atmospheres (O2, N2, and Ar), flash lamp annealing (millisecond duration) and pulse plasma annealing (microsecond duration). It is shown that the highest luminescence efficiency of RE3+ is obtained for the shallow implantation at RT with the optimal fluence of 1.0 × 1015 RE ions/cm2 followed by a 10 min annealing in oxygen at 800 °C, and the light emission from such a ZnO:RE system is so bright that can be observed with the naked eye.

Rare Earth Doped Zinc Oxide Nanophosphor Powder: A Future Material for Solid State Lighting and Solar Cells

A comprehensive review of up-conversion (UP) and down-conversion (DC) or down shifting of rare earth (RE) doped zinc oxide (ZnO) nanophosphors is presented. Research interest in the development of RE3+ doped ZnO for UP and DC nanophosphors has been encouraged by the potential application of these materials in light emitting diodes and different types of photovoltaic cells. A range of remarkable characteristics, which are organized into different sections describing the structure, optical, and luminescence properties of these materials, are discussed in detail. Undoped ZnO has two characteristic emissions in the ultraviolet and visible regions related, respectively, to excitonic recombination and intrinsic defects. X-ray photoelectron spectroscopy (XPS) data demonstrated a correlation between the visible emission and intrinsic defects. In the case of the DC or shifting process, there was simultaneous emissions related to f → f transitions of RE ions and defects in ZnO host. These emissions were dependent o...

Up-Conversion Mechanisms and Application of Rare Earth-Doped ZnO

Zinc oxide (ZnO) the film is a new type of transparent conductive oxides (TCO) material; it has a green environmental application prospect and hopeful to be substitution of indium tin oxide, so it has been the research focus of TCO materials. The rare earth ion like Yb3+, and Ho3+, Er3+shall be applied to satisfy the up-conversion function, and rare earth elements doped ZnO transparent conductive films will prepared. The play is to study the mechanism of up-conversion and energy transitions that the rare earth ions in the ZnO transparent conductive film. Through the theoretical analysis with the performance of the zinc oxide thin films explore optimization scheme, and aim to prepare out doped-ZnO and transparent conductive film that have both excellent photoelectric performance and up-conversion function. This new type of ZnO transparent conductive film with up-conversion function, it will have important theoretical significance in production of green environment materials and good application prospect in the field of sole cells, photoelectric detection luminescent device and so on.

Effect of temperature on excited state life-times of rare earth doped zinc oxide phosphors

Doped zinc oxide phosphors were synthesized and excited by high-peak power pulsed UV laser at room temperature as well as at liquid nitrogen temperature. There is considerable decrease in the values of life-time at low temperature (77 K), whereas mixed trend is observed in life-time values with change in concentration of didymium, which indicates the perturbation effect in host material. The increased fluorescence quantum yield, emission efficiency and down-conversion phenomena of these selective radiative transitions, in doped phosphors, make them a very promising material for laser medium, vacuum fluorescent displays, fluorescent lamps, information storage and optoelectronic industry.

Non-linearity in rare earth doped zinc oxide varistor prepared by flash combustion method

A novel processing technique involving flash combustion of nitrate-urea mixtures has been reported for praseodymium doped zinc oxide containing K 2O in the range 0·0–0·5 mol%. The starting average powder particle size was 2 μm with a tap density of 1250 kg/m 3. The non-linear behaviour of the prepared zinc oxide varistor was examined in the field range 200–650 V/mm. The breakdown voltage was seen to attain a maximum value of about 600 V/mm in compositions containing 0·3 mol% K 2O. The variation of breakdown voltage is explained on the basis of the microstructure and K 2O content.