采用气相传输平衡(VTE)技术,在(0001)面白宝石衬底表面上成功地制备出单相-γL iA lO2层。研究了白宝石衬底表面形貌对-γL iA lO2层质量的影响,发现白宝石衬底的表面粗糙度和退火处理是两个影响-γL iA lO2层质量的重要因素。要制备高...采用气相传输平衡(VTE)技术,在(0001)面白宝石衬底表面上成功地制备出单相-γL iA lO2层。研究了白宝石衬底表面形貌对-γL iA lO2层质量的影响,发现白宝石衬底的表面粗糙度和退火处理是两个影响-γL iA lO2层质量的重要因素。要制备高质量的-γL iA lO2层,适度的表面粗糙度是恰当的。对白宝石衬底进行退火处理,-γL iA lO2层的择优取向变差。并对其中可能的机理进行了探讨。展开更多
γ-LiAlO2:Eu3+(Eu3+:LAO) phosphor was obtained by gel combustion method using LiNO3,Al(NO3)3·9H2O,Eu(NO3)3·6H2O and citric acid as raw materials.The structure,morphology and luminescence were characterized b...γ-LiAlO2:Eu3+(Eu3+:LAO) phosphor was obtained by gel combustion method using LiNO3,Al(NO3)3·9H2O,Eu(NO3)3·6H2O and citric acid as raw materials.The structure,morphology and luminescence were characterized by means of X-ray diffraction (XRD),scanning electron microscopy (SEM),photoluminescence (PL).The results demonstrated that the phosphor was pure-phase of flaky tetragonal crystal system with a mean size of around 1 μm.The strongest excitation peak was at 254 nm,belonging to the broadband excitation and the maximum emission peak was at 613 nm,corresponding to the 5D0→7F2 transition of Eu3+.Luminous intensity is closely related to the calcination temperature and doping concentration of Eu3+.展开更多
ZnO thin films were deposited on the substrates of (100) γ-LiAlO2 at 400, 550 and 700℃ using pulsed laser deposition (PLD) with the fixed oxygen pressure of 20 Pa, respectively. When the substrate temperature is 400...ZnO thin films were deposited on the substrates of (100) γ-LiAlO2 at 400, 550 and 700℃ using pulsed laser deposition (PLD) with the fixed oxygen pressure of 20 Pa, respectively. When the substrate temperature is 400℃, the grain size of the film is less than 1 μm observed by Leitz microscope and measured by X-ray diffraction (XRD). As the substrate temperature increases to 550℃, highly-preferred c-orientation and high-quality ZnO film can be attained.While the substrate temperature rises to 700℃, more defects appears on the surface of film and the ZnO films become polycrystalline again possibly because more Li of the substrate diffused into the ZnO film at high substrate temperature. The photoluminescence (PL) spectra of ZnO films at room temperature show the blue emission peaks centered at 430 nm. We suggest that the blue emission corresponds to the electron transition from the level of interstitial Zn to the valence band. Meanwhile, the films grown on γ-LiAlO2 (LAO) exhibit green emission centered at 540 nm, which seemed to be ascribed to excess zinc and/or oxygen vacancy in the ZnO films caused by diffusion of Li from the substrates into the films during the deposition.展开更多
本文分析了在不同衬底上生长无极性GaN薄膜的情况,这些衬底主要包括-γL iA lO2、r面蓝宝石等。通常在蓝宝石上制备的GaN外延膜是沿c轴生长的,而c轴是GaN的极性轴,导致GaN基器件有源层量子阱中出现很强的内建电场,发光效率会因此降低,...本文分析了在不同衬底上生长无极性GaN薄膜的情况,这些衬底主要包括-γL iA lO2、r面蓝宝石等。通常在蓝宝石上制备的GaN外延膜是沿c轴生长的,而c轴是GaN的极性轴,导致GaN基器件有源层量子阱中出现很强的内建电场,发光效率会因此降低,发展非极性面外延,有望克服这一物理现象,使发光效率提高。展开更多
文摘采用气相传输平衡(VTE)技术,在(0001)面白宝石衬底表面上成功地制备出单相-γL iA lO2层。研究了白宝石衬底表面形貌对-γL iA lO2层质量的影响,发现白宝石衬底的表面粗糙度和退火处理是两个影响-γL iA lO2层质量的重要因素。要制备高质量的-γL iA lO2层,适度的表面粗糙度是恰当的。对白宝石衬底进行退火处理,-γL iA lO2层的择优取向变差。并对其中可能的机理进行了探讨。
基金Funded by Southwest University of Technology (No.08zx0103)
文摘γ-LiAlO2:Eu3+(Eu3+:LAO) phosphor was obtained by gel combustion method using LiNO3,Al(NO3)3·9H2O,Eu(NO3)3·6H2O and citric acid as raw materials.The structure,morphology and luminescence were characterized by means of X-ray diffraction (XRD),scanning electron microscopy (SEM),photoluminescence (PL).The results demonstrated that the phosphor was pure-phase of flaky tetragonal crystal system with a mean size of around 1 μm.The strongest excitation peak was at 254 nm,belonging to the broadband excitation and the maximum emission peak was at 613 nm,corresponding to the 5D0→7F2 transition of Eu3+.Luminous intensity is closely related to the calcination temperature and doping concentration of Eu3+.
基金supported by the Project of High Technology Research and Development of China(2006AA03A101 and 2006AA03A103)the National Natural Science Foundation of China(60676004)the Science Research Program of Shanghai(05PJ14100 and 06dz11402).
文摘ZnO thin films were deposited on the substrates of (100) γ-LiAlO2 at 400, 550 and 700℃ using pulsed laser deposition (PLD) with the fixed oxygen pressure of 20 Pa, respectively. When the substrate temperature is 400℃, the grain size of the film is less than 1 μm observed by Leitz microscope and measured by X-ray diffraction (XRD). As the substrate temperature increases to 550℃, highly-preferred c-orientation and high-quality ZnO film can be attained.While the substrate temperature rises to 700℃, more defects appears on the surface of film and the ZnO films become polycrystalline again possibly because more Li of the substrate diffused into the ZnO film at high substrate temperature. The photoluminescence (PL) spectra of ZnO films at room temperature show the blue emission peaks centered at 430 nm. We suggest that the blue emission corresponds to the electron transition from the level of interstitial Zn to the valence band. Meanwhile, the films grown on γ-LiAlO2 (LAO) exhibit green emission centered at 540 nm, which seemed to be ascribed to excess zinc and/or oxygen vacancy in the ZnO films caused by diffusion of Li from the substrates into the films during the deposition.
文摘本文分析了在不同衬底上生长无极性GaN薄膜的情况,这些衬底主要包括-γL iA lO2、r面蓝宝石等。通常在蓝宝石上制备的GaN外延膜是沿c轴生长的,而c轴是GaN的极性轴,导致GaN基器件有源层量子阱中出现很强的内建电场,发光效率会因此降低,发展非极性面外延,有望克服这一物理现象,使发光效率提高。
