P-type ZnO thin films prepared by in situ oxidation of DC sputtered Zn3N2:Ga

The feasibility of a new fabrication route for N and Ga codoped p-type ZnO thin films on glass substrates, consisting of DC sputtering deposition of Zn3N2:Ga precursors followed by in situ oxidation in high purity oxygen, has been studied. The effects of oxidation temperature on the structural, optical and electrical properties of the samples were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), optical transmittance and Hall effect measurements. The results were compared to a control film without Ga. XRD analyses revealed that the Zn3N2 films entirely transformed into ZnO films after annealing Zn3N2 films in oxygen over 500 ℃ for 2 h. Hall effect measurements confirmed p-type conduction in N and Ga codoped ZnO films with a low resistivity of 19.8 Ω?cm, a high hole concentration of 4.6E18 cm3 and a Hall mobility of 0.7 cm2/(V s). These results demonstrate a promising approach to fabricate low resistivity p-type ZnO with high hole concentration.     

Thickness dependence of the properties of transparent conducting ZnO:Zr films deposited on flexible substrates by RF magnetron sputtering

Transparent conducting zirconium-doped zinc oxide(ZnO:Zr)thin films with high transparency,low resistivity and good adhesion were successfully prepared on water-cooled flexible substrates(polyethylene glycol terephthalate,PET)by RF magnetron sputtering.The structural,electrical and optical prooerties of the films were studied for different thicknesses in detail.X-ray diffraction(XRD)and scanning electron microscopy(SEM)revealed that all the deposited films are polycrystalline with a hexagonal structure and a preferred orientation perpendicular to the substrate．The lowest resistivity achieved is 1.55×10-3 Ω·cm for a thickness of 189 nm with a Hall mobility of 17.6cm2/(V·s)and a carrier concentration of 2.15×1020cm-3.All the films present a high transmittance of above 90％in the wavelength range of the visible spectrum.     

衬底温度和氮气分压对氮化锌薄膜的性能影响

采用射频磁控溅射法在不同衬底温度和不同氮气分压下在石英玻璃衬底上制备氮化锌薄膜. 利用XRD和喇曼散射仪分析了样品的晶体结构和组成. 结果表明当氮气分压为1/2时可以生成多晶单一相的氮化锌薄膜. 利用霍尔效应和光学透过谱测量了样品的电学和光学性质. 结果表明衬底温度对样品的电学和光学性质有很大的影响. 衬底温度从100℃上升到300℃时,样品的电阻率从0.49降低到0.023Ω·cm. 电子浓度从2.7×1016升高到8.2×1019cm-3. 在衬底温度为200℃,氮气分压为1/2时,样品的光学带隙为1.23eV.     

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.     

电子束沉积技术生长WZO-TCO薄膜及其特性研究

采用电子束沉积技术生长w掺ZnO（WZO,ZnO：w）透明导电氧化物（TCO）薄膜（即WZO-TCO薄膜）并研究了衬底温度（100-350℃）对薄膜微观结构、表面形貌以及光电性能的影响。实验表明,随着衬底温度的升高,薄膜的晶体质量取得明显改善（从非晶化状态转变到结晶状态）,生长的WZO薄膜呈现C轴择优取向[即（002）...     

The effect of growth conditions,point defects and hydrogen on the electronic structure and properties of p-type (Al,N) codoped ZnO: A first principles study

The effects of point defects, hydrogen, and growth conditions on the electronic structure and properties of the (Al,N) codoped p-type ZnO have been investigated using the first principles method. The obtained results showed that the Al_Zn–N_O–V_Zn complex is a shallow acceptor that can play an important role in achieving the p-type conductivity in the (Al,N) codoped ZnO films. Our results showed also that the electrical conductivity type in the (Al,N) codoped ZnO films strongly depends on the donor/acceptor concentrations ratio. The codoped ZnO films prepared under both Zn-rich and O-rich growth conditions with a donors/acceptors ratio of 1:2 have a p-type conductivity, while those prepared with a ratio of 1:1 cannot be p-type unless if they are prepared under O-rich conditions. The achieved p-type quality depends also on the used nitrogen doping source. To prepare p-type ZnO film of high quality using the (Al,N) codoping method, the use of NO or NO₂ is recommended. The presence of donor defects such as oxygen vacancies and hydrogen will significantly affect the electronic properties of the (Al,N) codoped ZnO films, and if the concentration of these defects in the sample is high enough, the material can be easily converted to n-type.     

WZO薄膜生长及氧流量对其特性的影响

采用直流脉冲反应磁控溅射方法生长W掺杂ZnO(ZnO:W,即WZO)透明导电氧化物(TCO)薄膜并研究了氧气流量对薄膜微观结构、组分、表面形貌以及光电性能的影响。实验结果表明,WZO薄膜具有良好的(002)晶面择优取向生长,且适当的氧气流量是制备优质WZO薄膜的关键因素。WZO薄膜表面形貌受薄膜结晶质量的影响。当氧气流量为2.08×10-7 m3/s时,WZO薄膜在400～1 500nm透过率达到84.5%,电阻率为4.61×10-3Ω.cm,迁移率为20.5cm2v-1s-1。XPS测试表明WZO薄膜中Zn和W均处于氧化态,其中W元素呈现W6+价态。     

衬底温度对磁控溅射法制备的ZnO:In薄膜光电性能的影响

以粉末靶为溅射源,采用射频磁控溅射法在玻璃衬底上制备掺铟氧化锌(ZnO:In)透明导电膜.利用X射线衍射仪、原子力显微镜、霍尔测试仪,以及分光光度计等对不同衬底温度下生长的ZnO:In薄膜的结构、光电性能进行表征.结果表明,所有制备的ZnO:In薄膜均为六角纤锌矿结构的多晶膜,具有(002)择优取向.ZnO:In薄膜的电阻率随着衬底温度的升高先减小后增大,当衬底温度为100℃时,薄膜的最低电阻率为3.18×10~(-3)Ω·cm.制备的薄膜可见光范围内透过率均在85%以上.

Abstract：

Indium doped zinc oxide (ZnO : In) films were deposited on glass substrates by RF magnetron sputtering method using a powder target.The influence of the substrate temperature on the structure,optical and electrical properties was investigated by X-ray diffraction (XRD),atom force microscope (AFM),Hall measurement and optical transmission spectroscopy.The results show all the obtained films are polycrystalline with a hexagonal wurtzite structure and grow preferentially in the (002) direction,and the grain size is about 22～29 nm.The conductivity of the ZnO : In films change with the substrate temperature,and the lowest electrical resistivity is about 3.18 × 10~3 Ω·cm for the samples deposited at substrate temperature 100 ℃.The transmittance of our films in the visible range is all higher than 85%.     

Electrodeposition and characterization of ZnO thin films using sodium thiosulfate as an additive for photovoltaic solar cells

Zinc oxide thin films have been grown by electrodeposition technique onto Cu and ITO-coated glass substrates from an aqueous zinc nitrate solution with addition of sodium thiosulfate at 90℃.The effects of sodium thiosulfate on the electrochemical deposition of ZnO were investigated by cyclic voltammetry and chronoamperometry techniques.Deposited films were obtained at -0:60 V vs.SCE and characterized by XRD,SEM,FTIR, optical,photoelectrochemical and electrical measurements.Thickness of the deposited film was measured to be 357 nm.X-ray diffraction results indicated that the synthesized ZnO has a pure hexagonal wurtzite structure with a marked preferential orientation along (002) plane.FTIR results confirmed the presence of ZnO films at peak 558 cm^-1.SEM images showed uniform,compact morphology without any cracks and films composed of large flower-like ZnO agglomerates with star-shape.Optical properties of ZnO reveal a high optical transmission (>80%) and high absorption coefficient (α>105 cm^-1)in visible region.The optical energy band gap was found to be 3.28 eV.Photoelectrochemical measurements indicated that the ZnO films had n-type semiconductor conduction.Electrical properties of ZnO films showed a low electrical resistivity of 6.54 Ω·cm,carrier concentration of -1.3×10¹⁷cm^-3 and mobility of 7.35 cm²V^-1s^-1.     

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.     

Properties of antimony doped ZnO thin films deposited by spray pyrolysis technique

Antimony (Sb) doped zinc oxide (ZnO) thin films were deposited on the glass substrate at 450°C using spray pyrolysis technique. Effect of Sb doping on surface morphology structural, optical and electrical properties were studied. X-ray diffraction (XRD) analysis showed that both the undoped and doped ZnO thin films are polycrystalline in nature with (101) preferred orientation. SEM analysis showed a change in surface morphology of Sb doped ZnO thin films. Doping results in a marked increase in conductivity without affecting the transmittance of the films. ZnO films prepared with 3 at % Sb shows the lowest resistivity of 0.185 Ohm cm with a Hall mobility of 54.05 cm² V^–1 s^–1, and a hole concentration of 6.25 × 10¹⁷ cm^–3.     

Fabrication of p-Type ZnO Thin Films via DC Reactive Magnetron Sputtering by Using Na as the Dopant Source

The Na-doped p-type ZnO thin films were prepared by DC reactive magnetron sputtering. Two types of substrates were used for separate testing purposes: silicon wafers for crystallinity measurements and glass slides for electrical and optical transmittance measurements. The lowest room-temperature resistivity under the optimal condition was 59.9 Ω cm, with a Hall mobility of 0.406 cm² V⁻¹s⁻¹ and a carrier concentration of 2.57 × 10¹⁷ cm⁻³. The Na-doped ZnO thin films possessed a good crystallinity with c-axis orientation and a high transmittance (∼85%) in the visible region. The effects of the substrate temperature on the crystallinity and the electrical properties were discussed.     

Synthesis and characterization of phosphorus-doped ZnO and (Zn,Mg)O thin films via pulsed laser deposition

The transport and optical properties of phosphorus-doped (Zn,Mg)O thin films grown via pulsed laser deposition (PLD) are studied. The carrier type of as-deposited (Zn,Mg)O:P films converts from n-type to p-type with increasing oxygen partial pressure. All the films exhibit good crystallinity with c-axis orientation. This result indicates the importance of oxidation conditions in realizing p-type (Zn,Mg)O:P films. The as-deposited ZnO:P film properties show a strong dependence on the deposition ambient at different growth temperatures. The resistivity of the samples deposited in O₃/O₂ mixture is two orders of magnitude higher than the films grown in oxygen and O₂/Ar/H₂ mixture. The room-temperature photoluminescence (PL) of the as-deposited films has been shown that growing in the O₂/Ar/H₂ mixture ambient significantly increases the band edge emission while inhibiting the visible emission. The enhanced ultraviolet (UV) emission in the films grown in O₂/Ar/H₂ mixture may result from hydrogen passivation of the deep level emission centers. The annealed ZnO:P films are n-type with nonlinear dependence of resistivity on annealing temperature. The resistivity increases in the films with annealing at 800°C while decreasing with further increasing annealing temperature. Strong visible light emission is observed from the ZnO:P films annealed in oxygen.     

Optimization of N2/Ar gas flow ratio for the realization of nitrogen-doped p-type ZnCdO thin films synthesized by RF magnetron sputtering

Nitrogen doped ZnCdO films [ZCO:N] have been grown on quartz substrates by radio frequency (RF) reactive magnetron sputtering technique, and the effect of the ratio of nitrogen to argon gas flow [N₂:Ar] on their electrical, microstructure and optical properties were investigated by Hall effect, energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), transmission electron microscope (TEM), optical absorbance and photoluminescence (PL) measurements. The results indicate that all the ZCO:N films are of hexagonal wurtzite structure with highly (002) preferential orientation. As the N₂:Ar increases from 0:1 to 4:1, the absorption edge for the samples exhibits blue shift. Hall effect measurement results indicate that the N₂:Ar exerts an immense influence on the p-type conduction conversion for ZCO:N film. It is found that ZCO:N film deposited at the N₂:Ar of 1:2 shows the optimal p-type behavior, which has a carrier concentration of 1.10×10¹⁷ cm⁻³, a mobility of 3.28 cm²V⁻¹s⁻¹ and a resistivity of 17.3 Ω cm. Compared with the other samples, ZCO:N film fabricated at the relatively lower N₂:Ar possesses the superior crystal quality, luminescent and electrical properties. Additionally, a possible mechanism of p-type conduction for ZCO:N film was discussed in this work.     

Optical,morphological and electrical studies of Zn:PbS thin films

Structural, electrical, and optical properties of undoped and Zn doped lead sulfide (PbS) thin films are benign reported in this paper. The subjected films were grown on glass substrates at 25 °C by a chemical bath deposition (CBD) method. The concentration of Zn in the deposition bath represented by the ratio [Zn²⁺]/[Pb²⁺] was varied from 0% to 5%. It was found that the film׳s grains decreased in size with increasing Zn content in the film. XRD data showed the polycrystalline nature of the film its crystal orientation peak intensities decreased with higher doping concentration of Zn. Atomic force microscopy (AFM) measurements revealed that the surface roughness of the films decreased due to zinc doping as well. However, with increasing of the dopant concentration from 0% to 5%, the average transmittance of the films varied over the range of 35–75%. The estimated optical band (E_g) gaps of undoped and Zn doped PbS thin films were in the range of 0.72–1.46 eV. Hall Effect measurements electrical resistivity, carrier concentration and Hall mobility have been determined for the titled film as functions on the Zn content within the film׳s textures. The overall result of this work suggested that the Zn:PbS film is a good candidate as an absorber layer in the modern solar cell devices.     

ZnO薄膜的射频磁控溅射制备及性能研究

采用射频磁控溅射法在玻璃衬底上制备出高质量的ZnO薄膜.对薄膜的结构和性能进行了研究.所制备的ZnO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.ZnO薄膜的霍尔迁移率和载流子浓度分别为8×104m2/(V·s)和11.3×1020 cm-3.     

掺钛氧化锌透明导电薄膜的制备及特性研究

利用直流磁控溅射法在室温水冷玻璃衬底上成功地制备出了掺钛氧化锌(ZnO:Ti)透明导电薄膜.研究了靶衬间距对ZnO:Ti薄膜结构、形貌和光电性能的影响.研究结果表明,靶衬间距对ZnO:Ti薄膜的结构和电阻率有显著影响.X射线衍射(XRD)表明,ZnO:Ti薄膜为六角纤锌矿结构的多晶薄膜,且具有c轴择优取向.在靶衬间距为4.6 cm时,实验获得的ZnO:Ti薄膜电阻率具有最小值4.18×10-4Ω·cm.实验制备的ZnO:Ti薄膜具有良好的附着性能,可见光区平均透过率超过92%.ZnO:Ti薄膜可以用作薄膜太阳能电池和液晶显示器的透明电极.     

玻璃和聚酰亚胺衬底上磁控溅射沉积的ZnO:Al透明导电膜的结构、电学和光学性能(英文)

利用射频磁控溅射方法在玻璃和聚酰亚胺膜(PI)衬底上沉积了氧化铝质量分数为2%的掺铝氧化锌透明导电薄膜(ZnO∶Al)。系统地研究了不同衬底材料对薄膜的结构、电学以及光学性能的影响。分析表明,衬底材料对薄膜的结晶性和电学性能有较大的影响,对可见光透射率却影响不大。X射线衍射(XRD)分析得出所有的ZnO∶Al具有良好的c轴择优取向性,在可见光区(400～800nm)两种衬底上的薄膜都达到了85%的透射率。玻璃衬底上的薄膜呈现出更强的(002)衍射峰及相对更小的半峰全宽(FWHM),薄膜电阻率达到了2.352×10-4Ω.cm。电镜分析表明,相对于PI上的ZnO∶Al膜,玻璃上ZnO∶Al膜表面有更致密的微观结构及更大的晶粒尺寸。PI衬底上的ZnO∶Al膜也有相对较好的电、光学性能,其中电阻率达到了6.336×10-4Ω.cm,而且由于PI衬底柔性可弯曲,使得它适于在柔性太阳电池和柔性液晶显示中做窗口层材料及透明导电电极。玻璃上的ZnO∶Al膜则可应用在平板显示和太阳电池技术中。     

Studies on morphology,electrical and optical characteristics of Al-doped ZnO thin films grown by atomic layer deposition

Al doped ZnO (AZO) films deposited on glass substrates through the atomic layer deposition (ALD)technique are investigated with various temperatures from 100 to 250 ℃ and different Zn ∶ Al cycle ratios from 20 ∶ 0 to 20 ∶ 3.Surface morphology,structure,optical and electrical properties of obtained AZO films are studied in detail.The Al composition of the AZO films is varied by controlling the ratio of Zn ∶ Al.We achieve an excellent AZO thin film with a resistivity of 2.14 × 10-3 Ω·cm and high optical transmittance deposited at 150 ℃ with 20 ∶ 2 Zn ∶ Al cycle ratio.This kind of AZO thin films exhibit great potential for optoelectronics device application.     

梯度掺杂生长绒面结构ZnO:B-TCO薄膜及其特性研究

采用新的金属有机化学气相淀积(MOCVD)-ZnO镀膜工艺技术-梯度掺杂技术生长绒面结构。研究ZnO:B-TCO薄膜。结果表明,梯度掺杂技术可有效增加薄膜晶粒尺寸和提高光散射作用。并且,梯度掺杂技术有效地提高了薄膜在近红外区域的光学透过率,有利于应用于宽谱域薄膜太阳电池。生长获得的MOCVD-ZnO薄膜,其薄膜电子迁移率为24 cm2/V,电阻率为2.17×10-3Ω.cm,载流子浓度为1.20×1020cm-3,且在小于1 000 nm波长范围内的平均透过率大于85%。