Study on the physical properties of europium doped indium oxide thin films

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• 作者：Nasreddine Beji^a ; ^{beji.nasreddine@gmail.com" class="auth_mail" title="E-mail the corresponding author} ; Mehdi Souli^a ; Meriem Reghima^a ; Sonia Azzaza^b ; Safia Alleg^b ; Najoua Kamoun-Turki^a
• 关键词：Thin films ; Europium doping ; Annealing under nitrogen atmosphere and spray pyrolysis technique
• 刊名：Materials Science in Semiconductor Processing
• 出版年：2016
• 出版时间：December 2016
• 年：2016
• 卷：56
• 期：Complete
• 页码：20-28
• 全文大小：2128 K

文摘

Structural, morphological, optical and electrical properties of europium doped In₂O₃ thin films grown by spray pyrolysis technique are studied in this work. The atomic percentages of europium dopant in In₂O₃-based solution were y   = width="42" alt="View the MathML source" title="View the MathML source" src="/sd/grey_pxl.gif" data-inlimgeid="1-s2.0-S1369800116302268-si0014.gif">${\left(\frac{{[\mathit{Eu}}^{3+}]}{{[\mathit{In}}^{3+}]}\right)}_{\mathit{sol}}$=0; 0.1; 0.3 and 0.5 at%. All films crystallize into the body centered cubic structure. The preferred orientation peak along the (222) plane was changed to (400) after doping. It is further revealed a best crystallinity for y =0.3 at% followed by a noticeable increase of the grain size. Some structural and microstructural parameters are determined using Rietveld refinement of XRD patterns. The optical transmission of doped films was above 68% in the visible range. The optical band gap (E_g) is in the range of [3.43–3.51] eV. Optical constant such as refractive index (n), packing density (p), porosity, oscillator energy (E₀) an_d dispersive energy (E_d) were also studied in this report using envelope method based on transmission-reflection spectra. Electrical properties show a lowest resistivity (ρ) for a doping concentration equals to 0.3 at% reaching 0.031 Ω cm. At this doping ratio, an enhancement of free carrier concentration is also remarked. A heat treatment under nitrogen atmosphere is then applied on optimized In₂O₃:Eu (0.3 at%). A significant decrease of the resistivity is noted at 250 °C during 2 h reaching 0.004 Ω cm. These results lead to conclude that annealed In₂O₃:Eu(0.3 at%) can be a good candidate to be used in many optoelectronic devices and especially as optical window or transparent electrode in solar cells.