溶胶-凝胶法合成纳米ZnO∶Al的表征及光学性能

以六水硝酸锌和九水硝酸铝分别作锌源和掺杂剂,使用溶胶-凝胶(Sol-Gel)法合成纳米ZnO∶Al。采用X线衍射(XRD)分析、透射电子显微(TEM)分析、X线光电子能谱(XPS)分析、光致发光光谱(PL)分析等方法对纳米ZnO∶Al进行表征。实验结果表明,Sol-Gel法合成纳米ZnO∶Al颗粒为六方纤锌矿型结构,当前驱体摩尔浓度为0.25 mol/L、热处理450℃和掺杂Al摩尔分数为3%时,样品的结晶性良好;XPS也证实Al~(3+)掺杂进入到ZnO晶体中,样品呈类球形,颗粒大小随前驱体浓度的增大而减小;对应的室温PL光谱上近紫外发射峰和弱蓝光缺陷峰强度都随浓度的增大而减小。     

Bi掺杂ZnO籽晶层生长纳米ZnO薄膜性能研究

采用溶胶 凝胶法制备得到不同浓度Bi3+掺杂ZnO籽晶层,又进一步采用水热法合成了六方纤锌矿结构的ZnO纳米棒。通过X线衍射（XRD）、场发射扫描电子显微镜（FESEM）、光致发光（PL）谱等测试手段对样品结构、形貌和光学性能进行测试和表征。结果表明,在不同浓度Bi掺杂ZnO籽晶层上生长纳米ZnO薄膜,ZnO的晶体结构没有改变,均为六方纤锌矿结构,且(002)晶面的峰强明显高于其他晶面的峰强值;在FESEM电镜观察下发现,不同掺杂浓度Bi掺杂ZnO籽晶层上水热生长的纳米ZnO薄膜均为纳米棒状。PL光谱显示随着Bi掺杂量增加,样品的近紫外发射峰和晶格缺陷峰等峰值明显增大,且有红移现象产生。其中禁带宽度随着Bi掺杂量的增大而减小,说明Bi3+可以有效地调节ZnO的禁带宽度。     

Ga-N共掺氧化锌纳米线阵列制备及发光性能研究

采用化学气相沉积法（CVD）以一氧化氮（NO）和氧化镓（Ga2O3）为掺杂源,在c轴取向单晶蓝宝石衬底上外延生长镓氮（Ga-N）共掺氧化锌（ZnO）纳米线阵列。利用SEM, XRD, HRTEM, XPS, PL等测试手段对掺杂后的ZnO纳米线阵列进行结构、成分和光学性能表征。结果表明,Ga-N共掺ZnO纳米线阵列保持六方纤锌矿结构,沿（002）方向择优生长;掺杂元素在样品中均匀分布。随着掺杂浓度增加,纳米线由六棱柱结构转变为尖锥层状结构,长度由2 μm减小到1 μm,锥度增加至0.95;N 1s/Ga 2p/Zn 2p峰结合能向低能态方向移动。PL光谱分析表明,所有样品均出现紫外发光峰和绿光发光峰,不同掺杂浓度的缺陷发光强度不同。     

Cu掺杂对sol-gel法制备的ZnO∶Co薄膜发光特性的影响

采用溶胶-凝胶法制备了Cu、Co共掺的Zn0.95-xCo0.05CuxO(x=0,0.01,0.03,0.05)薄膜,并用金相显微镜和X射线衍射(XRD)研究了样品薄膜的形貌和结构,结果发现掺杂量影响着衍射峰的强度和位置。测量了样品的室温光致发光谱(PL谱),所有样品均观察到紫外发光带和蓝光发光带,同时伴随有较弱的绿光发光带。微量Cu掺杂能够显著提高ZnO∶Co薄膜的发光强度,对样品的发光机制进行了讨论。     

Cu掺杂对sol-gel法制备的ZnO:Co薄膜发光特性的影响

采用溶胶-凝胶法制备了Cu、Co共掺的Zn0.95-xCo0.05CuxO(x=0,0.01,0.03,0.05)薄膜,并用金相显微镜和X射线衍射(XRD)研究了样品薄膜的形貌和结构,结果发现掺杂量影响着衍射峰的强度和位置。测量了样品的室温光致发光谱(PL谱),所有样品均观察到紫外发光带和蓝光发光带,同时伴随有较弱的绿光发光带。微量Cu掺杂能够显著提高ZnO∶Co薄膜的发光强度,对样品的发光机制进行了讨论。     

ZnO/ZnFe2O4复合纳米粒子的制备及其特性研究

利用水热法制备了ZnO/ZnFe2O4纳米复合粒子。用扫描电子显微镜(SEM)、X射线衍射(XRD)、光致发光光谱(PL)对退火前后的ZnO/ZnFe2O4纳米粒子进行表征。研究结果表明, 退火后的ZnO/ZnFe2O4纳米复合粒子表现出更好的形貌和晶体质量, 主要由六角纤锌矿结构的ZnO和立方结构的ZnFe2O4构成。PL光谱显示, 退火后ZnO近带边的发光强度明显降低, 这是由于ZnO/ZnFe2O4形成了Ⅱ型能带结构实现了光生载流子分离的结果。对其光催化特性也进行了研究, 光照时间为3 h, 退火后的ZnO/ZnFe2O4纳米复合粒子表现出更优秀的光催化活性, 降解甲基橙的效率可达50.48%。另外, 还对其磁性进行了研究, 室温条件下, 纳米复合粒子表现为顺磁性, 而经过退火处理后表现出铁磁性。因此, ZnO/ZnFe2O4纳米复合粒子经退火后具备磁性光催化剂性能, 有一定的发展前景。     

Cu掺杂对ZnO量子点光致发光的影响

通过溶液法合成了Cu掺杂ZnO量子点。X射线衍射(XRD)和高分辨电子透射电镜(HRTEM)图像显示Cu掺杂ZnO量子点具有六角纤锌矿结构,晶粒大小为4～5nm。Cu掺杂抑制了ZnO量子点颗粒长大。室温光致发光(PL)谱观察到紫外带边和可见区两个发射峰。随着Cu掺杂浓度的增大,紫外荧光峰位发生缓慢红移,由366nm移到370nm;可见区发射峰位发生蓝移,由525nm移到495nm;同时,两个发射峰强度降低。光谱结果表明:Cu的掺入,一方面抑制表面与O空位有关的缺陷,在495nm出现了与Cu1+有关的发射峰;另一方面,Cu离子掺入ZnO量子点引入一些非辐射中心,降低了自由激子发射。     

ZnO纳米棒的低温制备及表征

以硝酸锌、氨水为原料,采用低温水浴法在不同的温度下大规模制备了团簇状ZnO纳米棒,采用扫描电子显微镜(SEM)、能谱分析(EDX)、X射线衍射(XRD)、室温光致发光(PL)等手段对ZnO纳米棒进行了表征.SEM结果表明,环境温度对ZnO的形貌和性质有很大的影响,随着温度增加,ZnO长径比越来越大,当温度为90℃时ZnO的平均直径100 nm,长度约为5 μm;EDX和XRD图谱表明,ZnO纳米棒是高纯的六角纤锌矿结构;对90℃条件下制备的ZnO进行光致发光性能测试,观察到波长位于423 nm附近有较强的蓝光发射.     

ZnO：Ag薄膜的结构对其紫外发光增强的研究

利用脉冲激光沉积方法(PLD),在Si(100)衬底上生长了银掺杂的氧化锌薄膜(ZnO:Ag),所用的激光波长分别是1064 nm和355 nm.通过x射线衍射分析发现,两种不同激光沉积样品的晶体结构有很大的区别.此外,由1064 nm激光制备的ZnO:Ag薄膜,在氧气中800℃的条件下退火一个小时后,在其光致发光(PL)谱中发现,样品的紫外发光峰强度随薄膜中Ag含量增加而急剧增强,但在同样条件下处理的由355 nm激光制备的薄膜,没有观察到类似现象.经过分析和比较,我们认为这种紫外发光增强的特殊现象,是ZnO:Ag薄膜中的纳米Ag颗粒所引起的局部等离子共振而导致.     

衬底退火温度对ZnO纳米结构形貌和发光特性的影响

利用热蒸发Zn粉的方法,在Au/掺铝氧化锌(AZO) /石英衬底上生长ZnO纳米结构。为了研究不同 温度退火后的衬底对生长的ZnO纳米结构的影响,Au/AZO/石英衬底在生长纳米结构前分别在 300、500和700℃真空下退火。Au/AZO/石英衬底的表面形貌用原子力显微镜(AFM)观测 。ZnO纳米结构的微结构、形貌和 光学性能分别用X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和荧光光 谱仪进行测量。结果表明,在未退火和300 ℃ 退火衬底上生长了大量的ZnO纳米棒,而在500℃退火衬底上沉积了大量ZnO纳米颗粒。单晶结构 的纳米棒的平均直径分别约50nm,其 生长机制为蒸气-液体-固体(VLS)生长机制。荧光光谱显示所有的样品 都存在紫外发光峰和深能级发射带,随着退火温度的升高,生长的纳米结构的紫外发光峰相 对强度增强,而深能级发射强度减弱。     

Interface properties of ZnO nanotips grown on Si substrates

ZnO nanotips have been grown on Si (100) using metalorganic chemical vapor deposition (MOCVD). The growth temperature is optimized for good crystallinity, morphology, and optical properties. ZnO nanotips exhibit a strong near band edge emission of ∼376 nm at room temperature with negligible green band emission. Pregrowth substrate treatment using diluted hydrofluoric acid (HF) and minimized oxygen exposure before the initial growth significantly reduces the interfacial SiO₂ thickness, while maintaining good morphology. An n-ZnO nanotips/p-Si diode is fabricated and its I–V characteristic is measured. The threshold voltage of the diode is found to be below 2.0 V with small reverse leakage current. The ZnO/p-Si diodes provide the possibility of integrating the ZnO nanotips with Si-based electronic devices.     

超声喷雾热解法制备ZnO：Eu薄膜

以醋酸锌（Zn（CH3COO）2）、氯化铕（EuCl3）水溶液为前驱体,采用超声喷雾热解（USP）方法在ITO导电玻璃衬底上沉积Eu掺杂ZnO（ZnO：Eu）薄膜。通过扫描电镜（SEM）、X射线衍射（XRD）和光致发光（PL）谱对ZnO：Eu薄膜的形貌、结构和光学性质进行了研究。SEM测试结果表明,超声喷雾热解法制备的...     

Photoluminescence study of ZnO varistor stability

Photoluminescence (PL) measurements were carried out on commercial ZnO varistor samples that were electrically stressed and/or annealed at different temperatures. Changes in the intensity of green and yellow luminescence centers were studied as a function of annealing treatment. It was found that the ZnO luminescence (green and yellow) decrease with increase in annealing temperature, reach a minimum at 700°C, and increase again beyond 800°C. Furthermore, these green and yellow luminescence bands observed in the PL spectra are quenched in the ZnO varistor samples, compared to pure ZnO. In an electrically stressed ZnO varistor sample, the luminescence intensity was found to be higher compared to the as-sintered varistor sample. Annealing of the stressed varistor sample resulted in a decrease of the luminescence intensity. These PL observations are consistent with previous deep level transient spectroscopy and doppler positron annihilation spectroscopy results. All of the experimental results are consistent with the ion migration model of degradation and can be explained using a grain boundary defect model.     

低压高温退火对Ag掺杂ZnO薄膜性质的影响

采用电子束蒸发在n-Si(100)衬底上沉积Ag掺ZnO(ZnO:Ag)薄膜,随后在200 Pa的O<,2>气氛下分别在500、600、700和800℃退火4 h.用X射线衍射(XRD)仪、荧光光谱仪以及Van der Pauw方法测量ZnO:Ag薄膜的结构和光电学性质.结果表明,ZnO:Ag薄膜为多晶结构,且随着退火...     

Realization of intrinsic p-type ZnO thin films by metal organic chemical vapor deposition

P-type ZnO thin films were grown on sapphire substrates with and without nitrous oxide (N₂O) by metal organic chemical vapor deposition (MOCVD). The intrinsic p-type ZnO films were achieved by controlling the Zn:O ratio in the range of 0.05–0.2 without N₂O flow. Secondary ion mass spectroscopy (SIMS) showed that the films contained little or no nitrogen (N) impurities for all samples. The p-type behavior of the samples should be due to the intrinsic acceptor-like defects V_Zn, for ZnO film grown without nitrous oxide, and N, occupying O sites as acceptors for ZnO film grown with nitrous oxide. The best p-type ZnO film has low resistivity of 0.369 Ω-cm, high carrier density of 1.62×10¹⁹ cm⁻³, and mobility of 3.14 cm²/V-s. The obtained p-type ZnO films possess a transmittance of nearly 100% in the visible region and strong near-band-edge emission.     

垂直靶向脉冲激光沉积制备ZnO纳米薄膜

用一种新颖的制备纳米粒子与薄膜的垂直靶向脉冲激光沉积(VTPLD)方法,在室温及空气气氛下,于玻璃基底上成功地制备出ZnO纳米薄膜.用扫描电子显微镜(SEM)和X射线衍射(XRD)仪对ZnO纳米薄膜的表面形貌和结构进行了表征,用荧光光谱仪对薄膜的光致发光(PL)性能进行了测量.结果表明,当激光功率为13 W时,沉积出的粒子大小较均匀,尺寸在40 nm左右,且粒子排列呈现出一定方向性;当激光功率为21 W时,沉积的ZnO纳米薄膜图呈现出微纳米孔的连续薄膜.在玻璃基底上沉积的ZnO纳米薄膜有一主峰对应的(002)衍射晶面,表明ZnO纳米薄膜具有良好的c轴取向性.不同激光功率下沉积ZnO纳米薄膜经500 ℃热处理后的PL峰,其强度随激光能量而变化,最大发光波长位于412 nm.     

柔性衬底硅薄膜太阳电池中ZGO薄膜的应用

在室温下,采用孪生对靶直流磁控溅射工艺,在玻璃衬底上制备出高质量的Ga掺杂ZnO(ZnO:Ga)透明导电膜。研究了薄膜厚度对薄膜的结构、光学及电学特性的影响。制备的ZnO:Ga是具有六角纤锌矿结构的多晶薄膜,最佳择优取向为(002)方向。随着薄膜厚度的增加,衍射峰明显增强,晶粒增大。优化反应条件,薄膜的电阻率达到4.69×10-4Ω.cm,在可见光范围内平均透过率达到了85%以上。将不同厚度的ZnO:Ga薄膜(350～820 nm)在柔性聚酰亚胺衬底nip非晶硅(a-Si)薄膜太阳电池中,随厚度的增加,电池的填充因子和效率都得到了提高,得到聚酰亚胺衬底效率7.09%的a-Si薄膜太阳电池。     

Electrical properties of templateless electrodeposited ZnO nanowires

Electrochemical deposition allows the preparation of ZnO nanostructures with precisely controlled morphology and properties, by finely tuning the process parameters. ZnO nanowires were deposited onto gold substrates by electrodeposition from a low concentration zinc nitrate bath. Photolithography was employed for patterning interdigitated electrode systems onto silicon/silicon dioxide substrates and ZnO electrodeposition lead to wires connected to each other by bridging neighboring interdigits allowing electronic transport characterization. Optical measurements, i.e. reflection and photoluminescence spectroscopy, were performed and the results were correlated to electronic transport data. We found that we deal with a system for which one can apply a model of space charge limited currents with different traps energy distribution as a consequence of electrodeposition rate. Current versus temperature measurements show different behavior for lower and higher range of temperatures. Such nanowires, fabricated and contacted in a straightforward way, allow a wide area of applications ranging from conductometric bio- or chemo-sensors to optoelectronic devices.     

MOCVD法以NO气体为掺杂源生长p型ZnO薄膜

采用金属有机化学气相沉积方法在玻璃上生长了掺氮的低电阻p型ZnO薄膜．实验使用NO和N2O共同作为氧源，且NO同时作为掺氮源，二乙基锌作为锌源．X射线衍射测试表明薄膜具有c轴择优取向的结构特性，二次离子质谱分析证实了氮被掺入了ZnO薄膜．通过优化锌源流量获得了最高空穴浓度为1.97×10/up18/cm－3，最低电阻率为3.02Ω·cm的ZnO薄膜．