衬底温度对非极性ZnO薄膜结晶性能和发光特性的影响

采用金属有机化学汽相沉积(MOCVD)设备在LiGaO2(100)衬底上制备了结晶性能良好的非极性ZnO薄膜.研究了衬底温度对ZnO薄膜结晶性能的影响.X射线衍射(XRD)分析结果表明在衬底温度为500℃时可以获得高质量的(1100)晶面取向的非极性ZnO薄膜.采用原子力显微镜(AFM)观察ZnO薄膜的表面形貌及晶体尺...     

Nd,Ce共掺YAG透明陶瓷的制备及其光谱性能研究

采用固相反应真空烧结法首次制备出Nd3+和Ce3+的掺杂浓度分别为1.0 at;和0.3 at;,Nd、Ce共掺YAG透明陶瓷,并对样品的相结构、显微结构、光学透过率和光谱性能进行了表征.结果表明,Nd3+和Ce3+都进入了YAG 晶格,样品的平均晶粒尺寸约为5 μm,1.5 mm样品的光学透过率除吸收带外基本都在75 at;以上.采用 467 nm 的激发源对样品Ce3+的5d能级进行激发,Ce3+通过对Nd3+的能量转移,实现了Nd3+的近红外发射,主荧光发射峰位于在1064 nm处,荧光寿命为256 μs.     

Yb~(3+),Ho~(3+)共掺氧化钇透明陶瓷的制备及其性能

研究了共沉淀法制备Yb/Ho∶Y2O3纳米粉末及其透明陶瓷的烧结工艺,采用Y(NO3)3、Yb(NO3)3和Ho(NO3)3的混合溶液为母盐溶液,以氨水为沉淀剂,在不同pH值下,用共沉淀法制备得到了碱式硝酸盐前驱体沉淀。1100℃煅烧2h得到Yb/Ho∶Y2O3纳米粉末。采用0.5wt%的TEOS(正硅酸四乙酯)为添加剂,1700～1850℃真空烧结15～25h后,得到了Yb/Ho∶Y2O3透明陶瓷。     

异质衬底上HVPE法生长GaN厚膜的研究进展

氮化镓基(GaN)光电器件的快速发展,对GaN的质量提出更高的要求,同质外延可以避免由于失配引起的缺陷,厚膜生长是解决GaN体材料生长困难的有效手段.氢化物气相外延(HVPE)是目前最普遍的制备氮化镓厚膜的方法.衬底对于GaN厚膜的影响不可忽视,本文总结了在蓝宝石、碳化硅和铝酸锂衬底上制备GaN厚膜的研究进展,讨论了今后的研究方向.     

Growth and characterization of high-quality Mn-doped LiAlO_2 single crystal

<正>The growth of a Mn-doped LiAlO_2 single crystal by the Czochralski(CZ) method and the characterization of its spectroscopy and thermoluminescence(TL) are presented.The X-ray rocking curve and chemical etching analysis show that the as-grown crystal has good crystallinity.The full-width at half-maximum (FWHM) of the LiAlO_2(200)ωrocking curve is 23.2 arcsec and the etching pits density of the(100) plane is(1.6-4.0)×10~4 cm~(-2).The transmission spectrum indicates that the crystal is highly transparent in the 200-1500-nm wavelength range.The emission spectrum of the crystal consists of a peak around 579 nm when excited with 428-nm light.The TL spectra show that the LiAlO_2:Mn crystal has glow peaks at 150 and 172℃.The change of TL characteristics of the crystal before and after thermal annealing in the air is discussed,and the effect of annealing and irradiation on the evolution of defect types is analyzed.     

Characteristics of the crystalline and luminescence properties of a-plane GaN films grown on γ-LiAlO_2(302) substrates

A-plane GaN films are deposited on(302) γ-LiAlO 2 substrates by metalorganic chemical vapor deposition(MOCVD) . The X-ray diffraction(XRD) results indicate that the in-plane orientation relationship between GaN and LAO substrates is [010] LAO [0001] GaN and [203] LAO [1100] GaN with 0.03% and 2.85% lattice mismatch,respectively. Raman scattering results indicate that the strain in the films decreases along with the increase in the thickness of the films. In addition to the band edge emission at 3.42 eV,defects-related luminescence at 3.35 eV is observed in the photoluminescence(PL) spectra. The cathodoluminescence(CL) spectra indicate that the 3.35-eV emission is related to the V pits.     

过渡金属离子(Mn,Fe,Co)掺杂铝酸锂晶体的生长及光谱分析

采用提拉法分别生长了掺杂Mn、Fe以及Co元素的LiAlO2晶体,并对其结晶质量和光谱特性进行了研究.结果表明,LiAlO2:Mn、LiAlO2:Fe和LiAlO2:Co晶体的X射线双晶摇摆曲线半高宽分别为23.2 arcsec、12.9 arcsec和23.8 arcsec.LiAlO2:Mn与LiAlO2:Fe晶体在可见至近红外波段具有较高的透过率,而LiAlO2:Co晶体在500～700 nm波段存在吸收带;光致激发与发射光谱表明Mn2+在LiAlO2:Mn晶体中处于四面体晶体场内,而Fe3+替代Li+处于八面体格位;X射线激发发射光谱分析得出空气退火后γ-LiAlO2晶体出现了较强的缺陷发光,可归结为Li2O挥发后形成的F+心,而在同样退火条件下掺杂LiAlO2晶体中相应的缺陷发光不明显,说明Li2O的挥发被抑制,晶体的热稳定性得到了改善.