掺铝氧化锌透明导电薄膜的表面织构研究

利用中频直流磁控反应溅射法在玻璃衬底上首先制备了掺铝氧化锌(AZO)透明导电薄膜,然后利用5%的氯化铵(NH4Cl)溶液对制备的AZO薄膜进行表面织构。利用扫描电子显微镜(SEM)、四探针法和分光光度计分别测量并研究了织构前后薄膜的表面形貌、电学和光学特性。研究结果表明NH4Cl水溶液容易控制AZO的表面织构过程,并且可以获得较好的绒面。表面织构后,薄膜在可见光波段的平均反射率从12%降低到7.86%,而电阻率略有增大,该结果和表面织构结果一致。     

绒面AZO干法制备及性能研究

利用射频溅射方法,制得AZO透明导电膜,并用离子束刻蚀制备绒面,得到绒面AZO透明导电膜。比较刻蚀前后光电性能及表面形貌,发现透过率稍有下降,在可见光波段透过率在80%以上;电阻率略有上升,但仍保持在10-3?·cm数量级,最低为2.91×10-3?·cm;刻蚀后薄膜表面形貌变化较大,大多数薄膜表面呈现"坑状"结构,横向尺寸在0.5?1.0μm,开口角在120°左右,表面粗糙度从7.29nm上升到36.64nm。薄膜具有较好的表面微结构,在作太阳能电池前电极方面有较好的应用前景。     

各向同性腐蚀法制备多晶硅绒面

本文介绍了一系列利用各向同性腐蚀法制备多晶硅绒面的试验，腐蚀液为硝酸和氢氟酸的混合溶液，添加了醋酸稀释液是为了降低反应速度。通过优化各种参数，获得了腐蚀速度平缓，适合工业生产的多晶硅绒面，绒面分布均匀。随着反应的进行，腐蚀坑由微裂纹状转变为气泡状，经反射率测定表明绒面达到了较好的减反效果。     

CCP/ICP混合放电C4F8/Ar等离子体高、低频功率对AZO薄膜绒面效果的影响

室温下,采用射频磁控溅射方法在石英基片上制备掺铝氧化锌(AZO)透明导电薄膜。利用CCP/ICP混合放电C4F8/Ar等离子体对制得的AZO薄膜进行绒面处理。利用原子力显微镜(AFM)对薄膜表面形貌进行表征,利用光纤光谱仪分析放电产生的碳氟基团含量的变化。实验结果发现低频功率的增大能够有效增加等离子体中F原子的含量,进而提高薄膜的刻蚀效果,获得较好的绒面结构;但是高频功率变化对薄膜刻蚀效果影响较小。     

掺铝氧化锌薄膜表面织构机制的研究

采用氯化铵(NH4Cl)溶液对磁控溅射技术制备的掺铝氧化锌(AZO)薄膜进行表面织构,并对其表面织构机制进行研究.研究结果表明NH4Cl溶液优先与间隙锌、间隙铝等缺陷和晶界处的堆积铝反应,而较大的相对应力和稀疏表面有助于间隙锌、间隙铝等缺陷和堆积铝的形成.它们对NH4Cl对AZO薄膜的表面织构很关键.     

钒对Zn-Fe合金镀层耐蚀性的影响

在电镀液中加入钒盐,在A3钢表面电镀出Zn-Fe合金薄膜.采用稳态法和循环伏安法研究了Zn-Fe合金镀层在30℃下0.5 mol/L H2SO4溶液中的腐蚀行为,采用扫描电镜(SEM)和X射线衍射(XRD)分析了钒对镀层在腐蚀前后微观结构的影响,用交流阻抗法研究了钒对电极等效电路的影响.结果表明,加入钒盐能改变Zn-Fe合金镀层的晶面择优取向和织构系数,当钒盐加入量为0.50～0.75 g/L时,镀层变得均匀、致密,镀层的致钝电流密度Jpp和维钝电流密度Jp明显降低,极化电阻增大,在强酸性溶液中的耐蚀性能明显增强.     

绒面ZAO透明导电膜的制备工艺研究

绒面ZAO(ZnO∶Al,氧化锌铝)透明导电膜在硅基薄膜太阳能电池领域应用前景广阔,本文利用直流磁控溅射方法,采用氧化锌铝陶瓷靶材制备了ZAO透明导电膜,并用自制的腐蚀液对膜层进行腐蚀以便形成太阳能电池所需要的表面凹凸起伏的绒面结构。研究了不同镀膜温度对膜层性能的影响,不同退火条件下膜层热稳定性的变化情况,不同腐蚀时间下膜层电阻、透过率以及表面形貌的变化,结果表明,在相同真空度、溅射功率和节拍的情况下,220℃下制备的ZAO透明导电膜膜层性能最好,腐蚀时间为30 s时获得的绒面效果好。     

直流磁控溅射技术低温制备高电导和高透明的氢掺杂AZO薄膜

采用直流磁控溅射的方法制备掺铝氧化锌(AZO)透明导电薄膜,通过溅射过程中加入氢气的方法来降低AZO薄膜的电阻率。结果表明:通过加入氢气的方法能有效降低AZO薄膜的电阻率;在衬底温度为225℃的低温条件下,通过优化其它沉积参数,制备了电阻率最低为4.5×10~(-4)Ω·cm、可见光区平均透光率在90%的优质AZO薄膜。这说明在溅射过程中引入一定流量的氢气,H可以起到掺杂作用,提高AZO薄膜的电导率。     

利用脉冲直流磁控溅射制备ZnO:Al薄膜的研究

利用中频脉冲直流磁控溅射法制备了平面ZnO:Al(AZO)透明导电薄膜,研究了沉积压力、衬底温度和溅射功率对AZO薄膜光电性能、薄膜稳定性的影响.结果表明:在较低沉积压力、衬底温度及溅射功率下,可获得具有低电阻率、高透过率、高稳定性的AZO薄膜.     

一种新型腐蚀剂——醋酸钠溶液对单晶硅太阳电池表面织构化的作用

对晶向为(100)的p型单晶硅片进行表面刻蚀,制作减反射绒面。选用了一种新型的腐蚀剂,即醋酸钠(CH3COONa)溶液,用来腐蚀单晶硅太阳电池。通过分别改变醋酸钠溶液的浓度、温度以及腐蚀时间对硅片表面进行腐蚀发现,经醋酸钠溶液腐蚀后在硅片表面形成腐蚀坑大小适中、分布均匀的绒面结构。在醋酸钠溶液的质量分数为20%、温度为95℃、时间为40min的条件下腐蚀单晶硅片,在波长为700～1000nm之间获得较低的平均表面反射率,且最佳平均反射率为12.14%。从实验结果和成本因素考虑,这种腐蚀剂的成本很低,不易污染环境且重复性好,有利于大规模工业化制绒。     

Preparation of Al-doped ZnO transparent electrodes suitable for thin-film solar cell applications by various types of magnetron sputtering depositions

In order to determine the influence of different types of magnetron sputtering (MS) depositions on the characteristics of Al-doped ZnO (AZO) thin films appropriate for applications as transparent electrodes in thin-film solar cells, transparent conducting AZO thin films were prepared on glass substrates at 200 °C by direct current (dc) magnetron sputtering (dc-MS), radio frequency (rf)-MS and rf power superimposed dc-MS (rf + dc-MS) depositions using an MS apparatus with the same AZO target. AZO thin films prepared by an rf + dc-MS deposition exhibited both a higher deposition rate than that found with rf-MS depositions and a lower resistivity or higher Hall mobility than those found with dc-MS. The lower dc sputter voltage featured in rf-MS and rf ± dc-MS depositions, producing smoother surface morphology and better crystallinity than obtained with dc-MS depositions. The light scattering characteristics of surface-textured AZO thin films prepared by various types of MS depositions were evaluated by observing the surface texture and measuring the optical transmittance and the diffusive component; wet-chemical etching of the thin film surface was performed in a 0.1% HCl solution. The obtainable haze property in the range from visible to near infrared in AZO films prepared by an rf + dc-MS deposition was markedly better than that obtained with dc-MS depositions.     

High rate direct current magnetron sputtered and texture-etched zinc oxide films for silicon thin film solar cells

Aluminum-doped zinc oxide (AZO) films were prepared by in-line direct current (dc) magnetron sputtering on glass substrates. Four types of ceramic targets with 0.5 wt.% or 1 wt.% of aluminum oxide and different preparation methods, namely normal sintered, soft sintered and hot pressed, were employed. The influence of different target manufacturing processes, aluminum concentration and sputtering conditions on AZO films were investigated. Depending on the type of targets and deposition conditions, highly transparent films with low resistivity values in the range of 3.6-11 × 10^− 4 Ω cm were obtained. The etching behaviour in hydrochloric acid and the resulting light scattering properties of the AZO films were strongly influenced by the choice of the target and the deposition conditions. The most favourable films have been successfully applied in thin film solar cells with 1.1-μm microcrystalline silicon absorber layer leading to an initial efficiency of 7.8%.     

不同缓冲层对Al掺杂ZnO薄膜性能的影响

本文采用射频反应磁控溅射法在玻璃基底上分别以Al2O3和AZO为缓冲层制备ZnO:Al(AZO)薄膜,利用X射线衍射仪(XRD)、扫描电镜(SEM)、紫外-可见分光光度计等方法对薄膜的结构和光电性能进行表征。XRD和SEM的分析结果表明,在Al2O3和AZO缓冲层上生长的AZO薄膜均具有较好的C轴择优取向,薄膜表面光滑平整,薄膜的结晶质量得到改善;透射光谱表明所有样品在可见光范围内的透过率均超过80%;薄膜的导电性能得到提高。     

Influence of rapid thermal annealing on surface texture-etched Al-doped ZnO films prepared by various magnetron sputtering methods

The influence of rapid thermal annealing (RTA) on surface texture formation as well as the light management obtainable by wet-chemically etching was investigated for transparent conducting Al-doped ZnO (AZO) thin films prepared by various types of magnetron sputtering deposition (MSD) with an oxide target. Texture-etched AZO films prepared by an r.f. (13.56 MHz) power-superimposed d.c. magnetron sputtering deposition (rf + dc-MSD) exhibited a higher haze value than found in equivalent films prepared by d.c. MSD. The order that the RTA treatment and the etching were conducted considerably affected the obtainable surface texture. Conducting the etching after a heat treatment with RTA in air resulted in larger etch pits as well as higher haze values than were obtained in AZO films that were etched before the RTA. A high haze value generally above 70% in the range from visible to near infrared (at wavelengths up to 1200 nm) was obtained in texture-etched AZO thin films that were prepared by rf + dc-MSD and etched after RTA at a temperature of 500 °C for 3 min.     

Preparation and character of textured ZnO:Al thin films deposited on flexible substrates by RF magnetron sputtering

ZnO:Al thin films deposited on transparent TPT substrates by magnetron sputtering were etched in acetic acid solution. The effects of etching solution concentration and etching time on the structure and properties of ZnO:Al films were investigated. The obtained films had a hexagonal structure and a highly preferred orientation with the c-axis perpendicular to the substrate. The ZAO film etched in 1% acetic acid solution for 10 s had a pyramidal structure and an enhanced light scattering ability, the average transmittance and reflectance in the visible region were 72% and 26% respectively, the sheet resistance was 260 Ω/□. Both transmittance and reflectance of the films decreased as the etching solution concentration and etching time increasing. Etching had a negative effect on the conductive properties of ZAO films. The lowest sheet resistance was 120 Ω/□ for the ZAO film without etching.     

Texturization of ZnO:Al surface by reactive ion etching in SF<Subscript>6</Subscript>/Ar,CHF<Subscript>3</Subscript>/Ar plasma for application in thin film silicon solar cells

As-deposited sputtered ZnO:Al (AZO) thin films having high transparency (T?≥?85% at 550 nm of wavelength) and good electrical properties (ρ?=?2.59?×?10^?04 Ω cm) are etched to get suitable light trapping in thin film solar cells, using reactive ion etching method in sulfur hexafluoride–argon (SF₆/Ar) plasma and trifluoromethane–argon (CHF₃/Ar) plasma to texture their surface. Though the electrical properties of the films are not affected much by the etching process but significant increment in the average haze values in the wave length range of 350–1100 nm in the etched AZO films (19.21% for SF₆/Ar and 22.07% for CHF₃/Ar plasma etched) are found compared to as-deposited AZO films (5.61%). Increment in haze value is due to more scattering of light from the textured surface. These textured substrates are used as front transparent conducting oxide electrode for the fabrication of amorphous silicon solar cells. Solar cells fabricated on etched AZO substrates show 7.76% increase in conversion efficiency compared to as-deposited AZO substrates.     

In situ micro-Raman spectroscopic study of laser-induced crystallization of amorphous silicon thin films on aluminum-doped zinc oxide substrate

The effects of laser irradiation condition and deposition substrate on the laser crystallized 330?nm Si films structure were investigated using in situ micro-Raman spectroscopy. Results showed that crystallization of amorphous silicon (a-Si) films started at laser irradiation power density of 0.6?×?10⁵?W/cm² for 20?s. The crystalline volume fraction of Si films depended mostly on the laser power density but not on the laser irradiation time. The Si films on both smooth and textured aluminum-doped zinc oxide (AZO) substrates exhibited lower crystalline volume fraction and smaller average grain size than the Si films on glass did. The Si films on textured AZO revealed higher crystalline volume fraction and larger average grain size than the Si films on smooth AZO did. The stress in crystalline Si films was observed to be compressive on AZO and tensile on glass. The compressive stress in crystalline Si films on textured AZO was slightly less than that on smooth AZO. The present work indicated that the structure of crystalline Si films on textured AZO was improved than that on smooth AZO, which may be helpful to crystalline Si thin-film solar cell.     

Microstructural evolution of ZnO by wet-etching using acidic solutions

The characteristics of the wet-etching of ZnO thin films were investigated using hydrochloric and phosphoric acid solutions as etchants. The etch rate of ZnO films, using a highly diluted hydrochloric acid solutions at a concentration of 0.25% in deionized water, was determined to be about 120 nm/min, and linearly increased with increasing the acid concentration. The surface of ZnO(0001) etched by an HCl solution, observed by scanning electron microscopy, showed a rough morphology with a high density of hexagonal pyramids or cones with sidewall angles of about approximately 45 degrees. Moreover, the sidewall angles of the masked area were similar to those of the pyramids on the surface. In comparison, the surface of ZnO(0001) etched by a phosphoric acid had a smooth surface morphology. The origin of this difference is from the very initial stage of etching, indicating that the etch-mechanism is different for each solution. Furthermore, when H3PO4 was added to the HCl aqueous solution, the morphology of the etched surface was greatly enhanced and the sidewall angle was also increased to about 65 degrees.