层状钴基热电薄膜的制备及其激光感生热电电压效应

【作者】 袁圆；

【导师】 张鹏翔；

【作者基本信息】 昆明理工大学 ， 材料物理与化学， 2008， 硕士

【摘要】 本文以Bi_2-xPb_xSr₂Co₂O_y（BPSCO）与Ca₃Co₄O₉（CCO）为研究对象,利用固相法制备了BPSCO与CCO多晶靶材;采用脉冲激光沉积技术在蓝宝石衬底上制备了BPSCO、CCO薄膜;测量了其LITV信号,并研究了其中可能存在的物理机理。采用固相法成功制备了BPSCO化合物。研究表明:制备的多晶靶材具有单一的相,没有其他杂相存在;所有靶材沿c轴（001）方向择优生长。利用脉冲激光沉积（PLD）技术分别在倾斜角度为0度、5度与10度的蓝宝石衬底上制备了BPSCO薄膜,利用XRD表征了薄膜结构,测量了其LITV信号。结果表明:在800度下制备的BPSCO薄膜沿c轴（001）方向一致取向外延生长,薄膜具有较好的结晶性。LITV信号表明:随着掺杂量的增加,峰值电压先增加后减小。在x=0.4时,薄膜的峰值电压达到最大。薄膜的LITV峰值电压随薄膜厚度增加而指数衰减。利用固相法成功制备了CCO化合物。制备的多晶靶材具有单一的相,靶材沿c轴（001）方向择优生长。利用PLD技术在蓝宝石衬底上制备了一系列的CCO薄膜。研究了薄膜的生长条件;在倾斜衬底上制备了不同氧压,不同厚度的CCO薄膜,首次在倾斜蓝宝石衬底上制备了CCO薄膜,首次发现其激光感生热电电压（LITV）信号,讨论了原位氧压、薄膜厚度对LITV信号的影响。XRD测量结果表明:在衬底温度为800度时,CCO薄膜具有较好的结晶性,并沿c轴（001）方向生长。随着原位氧压的增加,薄膜在100Pa时外延生长,结晶性达到最佳;在200Pa时,薄膜结晶性最差,但其LITV信号灵敏度最强。LITV信号随薄膜厚度增加而减小。更多还原

【Abstract】 In this paper,Bi_2-xPb_xSr₂Co₂O_y（BPSCO）and Ca₃Co₄O₉（CCO）were investigated. BPSCO and CCO polycrystalline were papered by using solid-state reaction method. BPSCO and CCO thin films were prepared on sapphire substrates by using pulse laser deposition technology whose LITV signal were measured and related physical mechanism were discussed.BPSCO compounds were successfully prepared by using solid state reaction method. the result show that BPSCO polycrystalline were single phase,there is no unexpected phase. all of them were preferentially oriented to（001）plane.BPSCO thin films were prepared on vicinal-cut sapphire substrates whose titled angle is 0,5 and 10 respectively.X-ray diffraction was used to determine the micro-structure and orientation of BPSCO thin films.The results show that BPSCO thin films were preferentially oriented to（001）plane along c-axis,and exhibited good crystallinity.LITV signal show that with the increase in doping,the peak voltage increases first and then decreases,when doping is 0.4,the peak voltage reaches the highest value.The LITV peak voltage of thin films exponential decreases with the increasing of thickness of thin films.CCO compound was successfully synthesized by using solid-state reaction method. CCO polycrystalline has single phase,and preferentially oriented alone c-axis.PLD technology was used for preparing CCO thin films on vicinal-cut sapphire substrates.The growth condition of CCO thin films was systemic investigated.CCO thin films were prepared in different partial oxygen pressure and thickness,and then LITV signal were measured,the impact of partial oxygen and thickness on thin films were discussed.The result show that when temperature of substrate was 800,CCO thin films has good crystallinity,and grow alone（001）oriented in c-axis.When the partial oxygen increased, thin films expitaxial grow alone c-axis in 100 Pa.when the partial oxygen pressure reached 100 Pa,the thin film showed the best crystallinity while the crystallinity showed the worst in 200 Pa oxygen pressure.When oxygen pressure was 200 Pa,the LITV signal reached the highest value than other oxygen pressure.LITV decrease with the increase of thickness of thin films.更多还原