Structural, optical, and electrical properties of Yb-doped ZnO thin films prepared by spray pyrolysis method

Abstract

Yb-doped ZnO thin films were prepared on glass substrates by spray pyrolysis technique in order to investigate the insertion of Yb ions in the ZnO matrix and the related optical properties of the films. The molar ratio of Yb in the spray solution was varied in the range of 0-5 at. %. X-ray diffraction patterns showed that the undoped and Yb-doped ZnO films exhibit the hexagonal wurtzite crystal structure with a preferential orientation along ͓002͔ direction. No secondary phase is observed in Yb-doped ZnO films. All films exhibit a transmittance between 75 and 90% in the visible range with a sharp absorption onset about 375 nm corresponding to the fundamental absorption edge at 3.3 eV. The photoluminescence measurements show a clear luminescence band at 980 nm that is characteristic of Yb 3+ transition between the electronic levels 2 F 5/2 and 2 F 7/2. This is an experimental evidence for an efficient energy transfer from ZnO matrix to Yb 3+. Hall effect measurements showed low resistivities and high carrier mobilities which makes these films of interest to photovoltaic devices.

Investigation of the structural, optical and electrical properties of Nd-doped ZnO thin films deposited by spray pyrolysis

“…Note that such healing of the ZnO native defects strongly depends on the nature of the doping ion. Indeed this phenomenon is almost absent in Yb-doped ZnO thin films grown by the same deposition technique [18]. No emission from Nd 3+ ions is observed in the 400-1000 nm wavelength range indicating that there is no energy transfer from ZnO into Nd 3+ ions in our samples.…”

“…This is clearly evidenced in the inset of Figure 2 where the Nd signal has been amplified to make the understanding easier for the reader. This can be explained by the low solubility limit of Nd in ZnO with respect to the case of Yb as previously observed in Zn 1−x Yb x O thin films [18]. Indeed, the solubility of Nd 3+ ion is expected to be much lower than that of Yb 3+ , in relation to the ionic radii difference between these elements (Nd 3+ : 0.99Å and Yb 3+ : 0.87Å [34]).…”

“…Numerous techniques such as reactive evaporation, sputtering, pulsed laser deposition, sol-gel and spray pyrolysis were used for the growth of undoped and doped ZnO thin films [8][9][10][11][12][13][14][15][16]. It is well established that physical and chemical properties of ZnO can be largely modified upon doping [17][18][19][20][21]. Doping ZnO with rare earth ions was shown to lead to interesting optical and magnetic properties.…”

Свойства пленок ZnO : Er-=SUP=-3+-=/SUP=-, полученных золь-гель методом

“…При синтезе образцов с использованием золь-гель технологии трехзарядные ред-коземельные ионы образуют в кристаллической решетке нанокристаллического оксида цинка определенный тип регулярных оптических центров с характерным для дан-ного иона спектром. Известно, что ионы редкоземельных металлов могут занимать положение примеси, располо-женной на границе зерен ZnO [15]. Также присутствие вакансий ионизированного кислорода V O увеличивает вероятность наличия ионов Er 3+ в качестве примеси замещения в комплексе V O −Er 3+ .…”

Transparent conductive Nd-doped ZnO thin films

“…In view of specific PV applications, such as solar energy converters for Si solar cells, rare Earth (RE) elements such as Nd, Yb, or Eu doping in ZnO or in other oxide materials were used to obtain down-shifting effects [10][11][12][13][14]. More specifically, the effects of incorporation of Nd 3+ ions on the structure, microstructure, and chemical nature of Nd-doped ZnO thin films were investigated [15][16][17].…”