铜掺杂氧化锌薄膜的阻变特性

采用脉冲激光沉积法在SnO<,2>:F(FTO)衬底上制备了单一c轴取向生长的ZnO和ZnO:Cu薄膜,并对具有Au/ZnO/FTO和Au/ZnO:Cu/FTO三明治结构的器件进行了阻变特性测试.结果显示:两种器件在室温电场作用下均显示出双极可逆变阻特性;Cu掺杂使ZnO薄膜的开关比大幅增加,电流-电压曲线拟合结果显示...     

激光能量对脉冲激光沉积法制备ZnO薄膜性能的影响

脉冲激光沉积技术(PLD)易于获得高质量的氧化物薄膜已成为一种重要的制备ZnO薄膜的技术.采用脉冲激光沉积(PLD)(KrF准分子激光器:波长248 nm,频率5 Hz,脉冲宽度20 ns)方法在氧气气氛中以高纯Zn(99.999%)为靶材、在单晶硅和石英衬底表而成功生长了ZnO薄膜.通过X射线衍射仪、表面轮廓仪、荧光光谱仪、紫外可见分光光度计对合成薄膜材料的晶体结构、厚度、光学性质等进行了研究,分析了激光能量变化对其性能的影响.实验结果表明我们使用PLD法可以制备出(002)结晶取向和透过率高于75%的ZnO薄膜,激光能量为450 mJ的ZnO薄膜的发射性能较好,但激光能量的增加不能改善薄膜的透光率.     

ZnO薄膜器件欧姆电极的高掺杂接触法制备

利用脉冲激光沉积方法在Al/Si衬底上生长出了高质量的n型ZnO单晶薄膜。研究并总结了以金属Al材料制备ZnO薄膜器件欧姆电极的方法。选择功函数合适的金属作为电极材料,比如In、Ti和Al等,可以在n型ZnO薄膜上制作良好的欧姆电极。研究发现,在金属Al和n型ZnO膜之间生长一层高掺杂的AZO层,可得到比Al与n型ZnO直接接触更优良的欧姆性能。并且,通过高温退火可以有效提高金属Al电极的结晶质量和电导率,降低电极与n型ZnO界面处的接触势垒,从而实现优良的欧姆接触性能。     

聚合物分散液晶薄膜中随机激光辐射的实现

设计制作染料掺杂聚合物分散液晶薄膜激光器件,研究随机激光辐射行为。利用微胶囊法将激光染料、向列相液晶、手性剂、聚乙烯醇混合,制备掺杂两种激光染料的聚合物分散液晶薄膜。利用输出激光532 nm的Nd:YAG倍频脉冲激光器进行泵浦,在582～607 nm波段获得尖锐、离散的随机激光输出,阈值能量约为9 mJ,线宽约为0.3～0.4 nm。对于器件产生激光辐射的机制,利用环形腔理论进行了分析。对比掺杂单种激光染料的聚合物分散液晶薄膜激光器件,实验结果显示,同时混合不同类型的激光染料制备的聚合物分散液晶薄膜,能够实现较宽波段的随机激光输出。     

衬底温度对PLD法制备的ZnO:Ga薄膜结构和性能的影响

利用脉冲激光沉积法在石英衬底上制备了镓掺杂氧化锌(ZnO:Ga)透明导电薄膜,研究了衬底温度对薄膜的结构、表面形貌和光电性能的影响.研究表明:制备的ZnO:Ga薄膜是具有六角纤锌矿结构的多晶薄膜.随着衬底温度的增加,衍射峰明显增强,晶粒尺寸增大.当衬底温度为450℃时,薄膜的最低电阻率为8.5×10<'-4>Ω·cm,...     

脉冲激光沉积法Li-N双受主共掺p型ZnO薄膜的生长及其特性

采用脉冲激光沉积技术制备了Li-N双受主共掺杂p型ZnO薄膜,其中Li来自Li掺杂ZnO陶瓷靶,N来自N2O生长气氛.室温Hall测试发现Li-N共掺p型ZnO薄膜的最低电阻率为3.99Ω·cm,迁移率为0.17cm2/(V·s),空穴浓度为9.12×1018cm-3.PL谱测试发现了与Li受主和N受主态相关的发光峰,其受主能级分别约为120和222meV.由p-ZnO:(Li,N)薄膜制备的ZnO同质p-n结具有整流特性.     

脉冲激光沉积法Li-N双受主共掺p型ZnO薄膜的生长及其特性

采用脉冲激光沉积技术制备了Li-N双受主共掺杂p型ZnO薄膜,其中Li来自Li掺杂ZnO陶瓷靶,N来自N2O生长气氛.室温Hall测试发现Li-N共掺p型ZnO薄膜的最低电阻率为3.99Ω·cm,迁移率为0.17cm2/(V·s),空穴浓度为9.12×1018cm-3.PL谱测试发现了与Li受主和N受主态相关的发光峰,其受主能级分别约为120和222meV.由p-ZnO:(Li,N)薄膜制备的ZnO同质p-n结具有整流特性.     

基于PSD器件的脉冲激光三角法测距系统设计

脉冲激光三角法测距将半导体脉冲激光技术和PSD器件技术的优点相结合,特别适合应用于激光近炸引信等近场探测领域。本文提出了“脉冲激光三角法”这一测距技术方案,使用脉冲激光二极管作为激光源,利用PSD器件在激光脉冲激励下的脉冲堆积现象,实现了脉冲激光二极管与PSD激光三角法测距的结合。文章最终完成了脉冲激光三角法测距系统原理样机的设计与联调,测距精度优于10cm.     

飞秒激光沉积红外窗口类金刚石增透保护膜

脉冲激光沉积法是一种制备类金刚石膜(DLC膜)的新技术.总结了脉冲激光法制备DLC膜在激光源、脉宽、沉积气氛及薄膜掺杂等方面的发展趋势.建立了飞秒脉冲激光沉积DLC膜系统,在不同的沉积条件下(如:真空、氧气氛、掺硅等)开展了实验研究,阐明了不同沉积条件对DLC膜性能的影响规律.在硅、锗红外窗口上镀制了工程实用的DLC增...     

持效疏水二氧化硅增透膜的制备和研究

为了制备结晶质量好的Cu掺杂ZnO薄膜,研究其结构和光学性质,采用脉冲激光沉积方法,在Si衬底上选择不同的衬底温度来制备薄膜.实验成功制得了结晶质量较好的Cu掺杂ZnO薄膜.利用X射线衍射仪、扫描电子显微镜和荧光分光光度计对样品进行了测量和分析.所制备的样品均表现出高度的c轴择优取向,衬底温度为300℃时,薄膜表面形貌均匀致密;在样品的光致发光谱中,发现样品除了在380nm附近出现紫外发光峰外,在460nm附近出现了蓝光发光峰,真正意义上实现了ZnO薄膜的蓝光发射.结果表明,衬底温度对其晶体质量有较大影响.     

Optical and electrical properties of epitaxial (Mg,Cd)xZn1−xO, ZnO, and ZnO:(Ga,Al) thin films on c-plane sapphire grown by pulsed laser deposition

A consistent set of epitaxial, n-type conducting ZnO thin films, nominally undoped, doped with Ga or Al, or alloyed with Mg or Cd, was grown by pulsed laser deposition (PLD) on single-crystalline c-plane sapphire (0 0 0 1) substrates, and characterized by Hall measurement, and UV/VIS optical transmission spectroscopy.The optical band gap of undoped ZnO films at nearly 3.28 eV was shifted by alloying with Mg up to 4.5 eV and by alloying with Cd down to 3.18 eV, dependent on the alloy composition. In addition, highly doped ZnO:Al films show a blue-shifted optical absorption edge due to filling of electronic states in the conduction band.The Hall transport data of the PLD (Mg,Zn,Cd)O:(Ga,Al) thin films span a carrier concentration range of six orders of magnitude from 3 × 10¹⁴ to 3 × 10²⁰ cm⁻³, which corresponds to a resistivity from 5 × 10⁻⁴ to 3 × 10³ Ω cm. Structurally optimized, nominally undoped ZnO films grown with ZnO nucleation and top layer reached an electron mobility of 155 cm²/V s (300 K), which is among the largest values reported for heteroepitaxial ZnO thin films so far.Finally, we succeeded in combining the low resistivity of ZnO:Ga and the band gap shift of MgZnO in MgZnO:Ga thin films. This results demonstrate the unique tunability of the optical and electrical properties of the ZnO-based wide-band gap material for future electronic devices.     

p型ZnO薄膜制备的研究进展

ZnO是一种性能优异的"低温蓝光工程"宽带隙Ⅱ-Ⅵ族半导体材料,但因本征施主缺陷和施主杂质引起的自补偿效应等使ZnO很难有效地实现n型向p型导电的转变。为此,阐述了ZnO薄膜的p型掺杂机理,介绍了国内外研究者在抑制自补偿、提高受主掺杂元素固溶度及寻求合适的受主掺杂元素等方面p型ZnO薄膜的最新研究进展。研究表明:增加ZnO材料中N原子固溶度的各种办法如施主-受主共掺杂、超声雾化气相淀积及本征ZnO薄膜在NH3气氛下后退火等和选择IB族中的Ag为受主掺杂元素是实现ZnO薄膜p型导电的有效措施。期望通过本综述能为国内ZnO基器件应用的p型ZnO薄膜的制备提供新思路。     

脉冲激光沉积法制备氧化锌薄膜

ZnO是一种新型的Ⅱ-Ⅵ族半导体材料,具有优良的晶格、光学和电学性能,其显著的特点是在紫外波段存在受激发射。利用脉冲激光沉积法(PLD)在氧气氛中烧蚀锌靶制备了纳米晶氧化锌薄膜,衬底为石英玻璃,晶粒尺寸约为28-35 nm。X射线衍射(XRD)结果和光致发光(PL)光谱的测量表明,当衬底温度在100-250℃范围内时,所获得的ZnO薄膜具有c轴的择优取向,所有样品的强紫外发射中心均在378-385 nm范围内,深能级发射中心约518-558 nm,衬底温度为200℃时,得到了单一的紫外光发射(没有深能级发光)。这归因于其较高的结晶质量。     

ZnO薄膜紫外光敏特性及晶界势垒的研究

以二水合醋酸锌为原料,采用sol-gel法在石英衬底上制备了ZnO薄膜。用AFM观察表面形貌,通过测量真空条件下不同温度热处理后薄膜的I-V特性,拟合计算晶界势垒高度。研究了热处理温度对ZnO薄膜性能的影响。结果表明:经650℃热处理制备的ZnO薄膜样品具有较佳性能,结构均匀致密,粒径分布为20～32nm。在10V偏压和1.24×10–3W/cm2光强下,紫外光灵敏度为43.95;无光照条件下晶界势垒高度为0.079eV。紫外光照使晶界势垒高度下降为0.011eV,薄膜的紫外光灵敏度与势垒高度的相对变化密切相关。     

Recent Advances in ZnO-Based Light-Emitting Diodes

ZnO has attracted considerable attention for optical device applications because of several potential advantages over GaN, such as commercial availability of bulk single crystals and a larger exciton binding energy (~60 meV compared with ~25 meV for GaN). Recent improvements in the control of background conductivity of ZnO and demonstrations of p-type doping have intensified interest in this material for applications in light-emitting diodes (LEDs). In this paper, we summarize recent progress in ZnO-based LEDs. Physical and electrical properties, bandgap engineering, and growth of n- and p-type ZnO thin films are also reviewed.     

Solar hydrogen production of ZnO horn electrodeposited on carbon film

Solar hydrogen production by ZnO electrodeposited onto carbon films was systematically investigated by controlling the amount of the deposited ZnO, property of carbon, and surface activation by KOH treatment. Carbon films have been prepared by polymer solution casting method using PAN solution, and subsequently annealing process. The surface of carbon film became made more porous by chemically activating using KOH. And then, by electrochemical deposition, single crystalline ZnO horn was loaded on both carbon film and activated carbon film to ZnO-based hetero photocatalysts. Electrochemical deposition has been carried out to investigate the effect of ZnO-loading amount by varying deposition condition such as deposition time and concentration of zinc acetate solution. The size of ZnO horn deposited was highly dependent on initial concentration of Zn precursor and deposition time. The measurement of hydrogen production showed that photocatalytic ZnO has produced hydrogen 1.65 and 1.68 times more when deposited on non-activated carbon film and activated carbon film, respectively, than ZnO nanoparticle alone, on account of fast electron transfer due to high electrical conductivity of carbon film. Whereas, by chemically activating carbon film to activated carbon film through the base treatment, hydrogen production was increased only 1.02 times as much as that by ZnO deposited on non-activated carbon film. In this work, the results were discussed and reasoned and it was suggested that characteristics of carbon film would play the most important key role on enhancement of hydrogen production using ZnO-based hetero photocatalysts among various factors.     

脉冲激光制备ZnO压敏电阻薄膜

利用脉冲激光沉积技术，在光学玻璃基片上制备了性能良好的ＺｎＯ压敏多晶薄膜，其非线性系数ａ≥６，压敏转折电压约３．５Ｖ。     

Title: Using Alignment and 2D Network Simulations to Study Charge Transport Through Doped ZnO Nanowire Thin Film Electrodes

Factors affecting charge transport through ZnO nanowire mat films were studied by aligning ZnO nanowires on substrates and coupling experimental measurements with 2D nanowire network simulations. Gallium doped ZnO nanowires were aligned on thermally oxidized silicon wafer by shearing a nanowire dispersion in ethanol. Sheet resistances of nanowire thin films that had current flowing parallel to nanowire alignment direction were compared to thin films that had current flowing perpendicular to nanowire alignment direction. Perpendicular devices showed ～5 fold greater sheet resistance than parallel devices supporting the hypothesis that aligning nanowires would increase conductivity of ZnO nanowire electrodes. 2‐D nanowire network simulations of thin films showed that the device sheet resistance was dominated by inter‐wire contact resistance. For a given resistivity of ZnO nanowires, the thin film electrodes would have the lowest possible sheet resistance if the inter‐wire contact resistance was one order of magnitude lower than the single nanowire resistance. Simulations suggest that the conductivity of such thin film devices could be further enhanced by using longer nanowires.     

Flash‐Assisted Processing of Highly Conductive Zinc Oxide Electrodes from Water

Fabricating high‐quality transparent conductors using inexpensive and industrially viable techniques is a major challenge toward developing low cost optoelectronic devices such as solar cells, light emitting diodes, and touch panel displays. In this work, highly transparent and conductive ZnO thin films are prepared from a low‐temperature, aqueous deposition method through the careful control of the reaction chemistry. A robotic synthetic platform is used to explore the wide parameter space of a chemical bath system that uses only cheap and earth abundant chemicals for thin film deposition. As‐deposited films are found to be highly resistive, however, through exposure to several millisecond pulses of high‐intensity, broadband light, intrinsically doped ZnO films with sheet resistances as low as 40 Ω □^?1 can be readily prepared. Such values are comparable with state‐of‐the‐art‐doped transparent conducting oxides. The mild processing conditions (<150 °C) of the ZnO electrodes also enable their deposition on temperature sensitive substrates such as PET, paving the way for their use in various flexible optoelectronic devices. Proof‐of‐concept light emitting devices employing ZnO as a transparent electrode are presented.