Au点阵模板控制生长ZnO堆垒单晶棒

采用磁控溅射技术在Si(111)衬底上溅射Au薄膜,900℃退火生成Au点阵模板,在Au点阵模板上溅射ZnO薄膜,O2气氛下1 000℃退火制备了ZnO堆垒单晶棒。研究了不同直径Au点阵模板对ZnO单晶棒结构性能的影响。采用扫描电镜(SEM)、高分辨透射电子显微镜(HRTEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)对样品结构形貌进行了分析。结果表明,生成有序排列的ZnO棒均由诸多六方纤锌矿单晶堆垒而成,较小Au点阵生成单晶棒的直径约为100nm。室温光致发光PL谱表明在376nm出现一个较强近紫外发射,在488nm附近出现一个较宽的深能级绿光发射,说明所制备样品具有良好的发光特性。     

Phase transformation from cubic ZnS to hexagonal ZnO by thermal annealing

We have investigated the mechanism of phase transformation from ZnS to hexagonal ZnO by hightemperature thermal annealing. The ZnS thin films were grown on Si(001) substrate by thermal evaporation system using ZnS powder as source material. The grown films were annealed at different temperatures and characterized by X-ray diffraction(XRD), photoluminescence(PL), four-point probe, scanning electron microscope(SEM) and energy dispersive X-ray diffraction(EDX). The results demonstrated that as-deposited ZnS film has mixed phases but high-temperature annealing leads to transition from ZnS to ZnO. The observed result can be explained as a twostep process:(1) high-energy O atoms replaced S atoms in lattice during annealing process, and(2) S atoms diffused into substrate and/or diffused out of the sample. The dissociation energy of ZnS calculated from the Arrhenius plot of 1000/T versus log(resistivity) was found to be 3.1 eV. PL spectra of as-grown sample exhibits a characteristic green emission at 2.4 eV of ZnS but annealed samples consist of band-to-band and defect emission of ZnO at 3.29 eV and 2.5 eV respectively. SEM and EDX measurements were additionally performed to strengthen the argument.     

Effects of Annealing Temperature on Properties of ZnO Thin Films Grown by Pulsed Laser Deposition

ZnO thin films are deposited on n-Si（111） substrates by pulsed laser deposition（PLD） system. Then the samples are annealed at different temperatures in air ambient and their properties are investigated particularly as a function of annealing temperature. The microstructure, morphology and optical properties of the as-grown ZnO films are studied by X-ray diffraetion（XRD）. atomic force mieroseope（AFM）, Fourier transform infrared spectroscopy（FTIR） and photoluminescence（PL） spectra. The results show that the as- grown ZnO films have a hexagonal wurtzite structure with a preferred c-axis orientation. Moreover, the diameters of the ZnO crystallites become larger and the crystal quality of the ZnO fihns is improved with the increase of annealing temperature.     

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。     

Synthesis and Properties of Mg-doped ZnO Nanobelts

The chemical vapor deposition(CVD)growth method is applicable to produce high-yield single-crystalline ZnO nanobelts.The Mg-doped ZnO nanobelts with a smooth surface have been successfully synthesized.The morphology,microstructure and optical properties of the ZnO nanobelts were analyzed by X-ray diffraction(XRD),scanning electron microscope(SEM),transmission electron microscope(TEM),selective area electron diffraction(SAED),energy dispersive X-ray spectroscopy(EDS)and photoluminescence(PL)spectroscopy.Resu...     

用MOCVD方法在GaAs衬底上低温生长ZnO薄膜

采用二乙基锌(DEZn)和水(H2O)作为生长源,利用金属有机化学气相沉积(MOCVD)的方法,在100～400℃低温范围内,在GaAs(001)衬底上制备了ZnO薄膜.利用X射线衍射(XRD),室温PL,AFM,SEM研究了薄膜的晶体结构特性、发光特性及表面形貌特性.XRD分析表明ZnO薄膜具有很强的c轴取向,(002)峰的FWHM平均值为0.3°.当生长温度达到400℃时从SEM测量结果可以观察到薄膜表面呈六角状结晶.随着生长温度的升高,薄膜的晶粒尺寸变大,结晶质量得到提高但同时表面变粗糙.室温PL测量显示薄膜在370nm附近有强的近带边发射,没有观测到深能级发射峰.     

sol-gel法制备ZAO薄膜的结构与光学性能研究

采用溶胶—凝胶法在普通玻璃衬底上制备了ZAO(ZnO:A1)薄膜,利用XRD、SEM、紫外—可见光谱和光致发光光谱对所制备的AZO薄膜进行了表征,研究了ZAO薄膜的结构和光学性能.结果表明:ZAO薄膜的微晶晶相与ZnO一致,且具有c轴择优取向;ZAO薄膜在可见光区的透过率超过了88％,在350～575 nm范围内有强的...     

Investigation of the blue–green emission and UV photosensitivity of Cu-doped ZnO films

Cu-doped zinc oxide (ZnO:Cu) films were deposited on p-Si (100) substrates using radio-frequency reactive magnetron sputtering. The structure and optical properties of the films were characterized by X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and fluorescence spectroscopy. XRD and SEM results revealed that ZnO:Cu film had a better preferential orientation along the c-axis compared with pure ZnO film. The chemical state of copper and oxygen in ZnO:Cu films was investigated by XPS. The results suggest that the Cu ion has a mixed univalent and bivalent state. The integrated Cu²⁺/Cu⁺ intensity ratio increased with the O₂ partial pressure. Photoluminescence measurements at room temperature revealed a double peak in the blue regions and a green emission peak. The close relationship between the valence state of Cu ions and the blue–green emission is discussed in detail. A higher photocurrent was observed for ZnO:Cu films under UV illumination. UV photodetectors based on ZnO:Cu films have high sensitivity and fast response and recovery times. Under periodic UV illumination at 380 nm the ZnO:Cu films showed stable photocurrent growth and decay, so the films are potential candidate materials for UV photodetectors.     

表面覆盖退火对ZnO薄膜光学性质的影响

研究了暴露在空气中退火和表面覆盖蓝宝石基板退火对MOCVD生长的ZnO薄膜光学性质的影响.研究发现,暴露在空气中退火虽可以去除薄膜中的氢杂质,并在低温光致发光(PL)谱中观察到与氢相关的束缚激子峰消失,但是退火后样品室温PL谱中可观察到很强的可见光发射,表明样品中引入了大量的深能级,样品的自由激子发光没有增强.而表面覆盖蓝宝石基板退火的样品,有效去除了氢杂质,但没有观察到可见光发射,说明表面覆盖蓝宝石基板退火可以有效地保护ZnO表面不分解,不生成深能级中心.由于激子束缚中心的减少,表面覆盖退火样品的自由激子发射大大增强.     

Growth of Polarity-Controlled ZnO Films on (0001) Al<Subscript>2</Subscript>O<Subscript>3</Subscript>

The polarity control of ZnO films grown on (0001) Al₂O₃ substrates by plasma-assisted molecular-beam epitaxy (P-MBE) was achieved by using a novel CrN buffer layer. Zn-polar ZnO films were obtained by using a Zn-terminated CrN buffer layer, while O-polar ZnO films were achieved by using a Cr₂O₃ layer formed by O-plasma exposure of a CrN layer. The mechanism of polarity control was proposed. Optical and structural quality of ZnO films was characterized by high-resolution X-ray diffraction and photoluminescence (PL) spectroscopy. Low-temperature PL spectra of Zn-polar and O-polar samples show dominant bound exciton (I₈) and strong free exciton emissions. Finally, one-dimensional periodic structures consisting of Zn-polar and O-polar ZnO films were simultaneously grown on the same substrate. The periodic inversion of polarity was confirmed in terms of growth rate, surface morphology, and piezo response microscopy (PRM) measurement.     

One-pot synthesis of ZnO/reduced graphene oxide nanocomposite for supercapacitor applications

ZnO/reduced graphene oxide (RGO) nanocomposite films were prepared by the sol–gel deposition method using a combination of zinc acetate and graphite. The solution derived composite films were extensively characterized using high resolution transmission electron microscopy (HR-TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), UV–visible spectroscopy, photoluminescence emission measurements, and four probe measurements. It was found that a highly transparent film with low resistivity could be obtained with the addition of a small amount of RGO into the deposition precursor. The results also showed that the sintering temperature reduces the resistivity and transparency of the films. XRD measurements revealed that films sintered >500 °C exhibit additional peaks, and suggest nucleation of different phases of the films. As a demonstration, the ZnO/RGO composite was integrated into a supercapacitor, and the resulting energy storage performance was tested.     

Mn掺杂浓度对ZnO纳米薄膜的结构和光致发光的影响

Mn掺杂的ZnO基稀磁半导体材料由于具有独特的特性而受到人们广泛的关注。ZnO的激子束缚能高达60meV,具有优良的光学性质。因此,Mn掺杂的ZnO材料研究在磁性半导体领域广泛开展起来。文章采用溶胶-凝胶法制备了Mn掺杂的ZnO纳米晶,讨论了不同Mn含量对材料结构和光致发光的影响。XRD结果表明,所有的样品均具有六角纤锌矿结构,并且随着引入Mn含量的增加,样品的晶格常数增大。光致发光结果显示,随Mn含量的增加,样品的紫外发光峰先红移后蓝移。光致发光谱也显示,适量的Mn掺杂可以钝化样品的可见区发射,提高样品的光学质量。     

退火温度对生长在TiO2缓冲层上的ZnO薄膜的影响

采用电子束蒸发技术在TiO2缓冲层上沉积了ZnO薄膜,研究了不同的退火温度对薄膜晶化质量及发光性质的影响. 利用X射线衍射仪和扫描探针显微镜分析了薄膜样品的结构性质,利用荧光光谱仪研究了薄膜样品的光致发光性质. 分析结果表明,退火处理后的ZnO薄膜都沿c轴择优生长. 在600℃下退火的样品具有最强的（002）衍射峰、最强的紫外发射和最弱的可见光发射,其晶粒大小均匀,紧密堆积. 而对于在500和700℃下退火的样品,其可见光发射较强. 这表明在600℃下退火的样品具有最好的晶化质量.     

The effects of Al doping and post-annealing via intrinsic defects on photoluminescence properties of ZnO:Eu nanosheets

Europium (Eu) and Aluminum (Al) co-doped ZnO nanosheets were synthesized by a hydrothermal method. The effects of Al concentration as a dopant and post-annealing of ZnO:Eu nanosheets on its structural, electrical and optical properties were investigated in detail. Prepared samples were characterized structurally using X-ray diffraction (XRD), morphologically using scanning electron microscopy (SEM) and optically using photoluminescence (PL) spectroscopy analyses. No diffraction peak related to dopants in XRD spectrum along with shift in peaks angles relevant to ZnO proved that Al and Eu ions were doped successfully into ZnO nanosheets. This study recommends that extrinsic doping and intrinsic defects have impressive roles on transferring energy to Eu ions at indirect excitations. Based on photoluminescence observations, intra-4f transitions of Eu³⁺ ions at an excitation wavelength of 390 nm allow a sharp red luminescence. Also the results showed that optical properties of ZnO can be tuned by varying the amount of Al concentration. In comparison with annealed Al doped ZnO:Eu nanostructures, as-grown samples showed the stronger PL peaks which indicated the effective role of intrinsic defects beside of extrinsic doping on energy transfer from ZnO host to Eu³⁺ ions which consequently led to producing the strong red emission from these sites.     

Composite structure of ZnO films coated with reduced graphene oxide: structural,electrical and electrochemical properties

ZnO films coated with reduced graphene oxide (RGO-ZnO) were prepared by a simple chemical approach.The graphene oxide (GO) films transferred onto ZnO films by spin coating were reduced to RGO films by two steps (exposed to hydrazine vapor for 12 h and annealed at 600 ℃).The crystal structures,electrical and photoluminescence properties of RGO-ZnO films on quartz substrates were systematically studied.The SEM images illustrated that RGO layers have successfully been coated on the ZnO films very tightly.The PL properties of RGO-ZnO were studied.PL spectra show two sharp peaks at 390 nm and a broad visible emission around 490 nm.The resistivity of RGO-ZnO films was measured by a Hall measurement system,RGO as nanofiller considerably decrease the resistivity of ZnO films.An electrode was fabricated,using RGO-ZnO films deposited on Si substrate as active materials,for super capacitor application.By comparison of different results,we conclude that the RGO-ZnO composite material couples possess the properties of super capacitor.     

Synthesis of PbS:ZnO nanotrees by thermal evaporation:morphological, structural and optical properties

Nanotrees ZnO films are synthesized by thermal evaporation method on silicon and glass substrates. PbS powder (5 wt%) is used to obtain the nanostructure and growth modifications. ZnO films are compared with non-doped ones (ZnO film was dense structure without nanotrees). The deposited PbS:ZnO films exhibit polycrystalline orientation using X-ray diffraction (XRD), but the films without doping was less crystalline quality. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to characterize the morphology. SEM images (surface and cross section) was confirmed the nanotrees form for doped ZnO film. Energy dispersive X-ray detector (EDX) was used to verify the composition of prepared films. Ultraviolet-visible (UV-Vis), photoluminescence (PL) and micro Raman techniques were used to investigate the optical properties. The PL spectra intensities were found to increase for PbS:ZnO nanotrees. Up to our knowledge, no work has been published regarding the obtained ZnO nanotrees using PbS as dopant via simple thermal evaporation method.     

Effect of Temperature on Structural and Morphologic Properties of ZnO Films Annealed in Ammonia Ambient

ZnO thin films were prepared on Si(111) substrates by pulsed laser deposition (PLD). Then, the samples were annealed at different temperatures in NH₃ ambient and their properties were investigated particularly as a function of annealing temperature. The structure, morphology, and optical properties of ZnO films were studied by x-ray diffraction (XRD), Fourier transform infrared spectroscope (FTIR), scanning electron microscope (SEM), and photoluminescence (PL). The results show that the increase of annealing temperature makes for the improvement in the crystal quality and surface morphology below the temperature of 650°C. However, when the annealing temperature is above 650°C, the ZnO films will volatilize and, especially at 750°C, ZnO will volatilize completely.     

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...     

Effects of annealing on the characteristics of ZnO films deposited in various O2/(O2+Ar) ratios

C-axis oriented ZnO films are deposited on polished diamond substrates in various O₂/(O₂+Ar) ratios using the radio frequency (RF) magnetron sputtering technique and are subsequently annealed in oxygen ambience under the same conditions. Structural, morphologic and electrical properties of ZnO films are characterized by X-ray diffraction (XRD), high-resistance instrument, energy dispersive X-ray spectroscopy (EDS) and scanning electronic microscopy (SEM). As the O₂/(O₂+Ar) ratio increasing from 1/12 to 5/12, the crystallinity of the as grown ZnO films becomes better and the electrical resistivity increases slowly. After annealing, the ZnO films deposited in O₂/(O₂+Ar) =1/12 and 3/12 are improved greatly in crystallinity, and their electrical resistivity is enhanced by two orders of magnitude, while those deposited in O₂/(O₂+Ar) =5/12 are scarcely changed in crystallinity, and their resistivity is only increased by one order. In addition, the ZnO films deposited in O₂/(O₂+Ar) =3/12 and annealed in oxygen are with the best crystal quality and the highest resistivity.     

PLD法制备ZnO薄膜的退火特性和蓝光机制研究

通过脉冲激光沉积(PLD)方法,在O2中和100～500℃衬底温度下,用粉末靶在Si(111)衬底上制备了ZnO薄膜,在300℃温度下生长的薄膜在400～800℃温度和N2氛围中进行了退火处理,用X射线衍射(XRD)谱、原子力显微镜(AFM)和光致发光(PL)谱表征薄膜的结构和光学特性。XRD谱显示,在生长温度300℃时获得较好的复晶薄膜,在退火温度700℃时获得最好的六方结构的结晶薄膜;AFM显示,在此退火条件下,薄膜表面平整、晶粒均匀;PL谱结果显示,在700℃退火时有最好的光学特性。