反应溅射法制备AZO薄膜的结构和透明导电性能
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摘要
不同于常用的金属或氧化物靶材,本研究以表面粘贴Al片的Zn/Zn O混合物(Al@Zn/Zn O)为靶材,在衬底温度(Ts)为150℃和300℃,溅射气氛为Ar+O2和Ar+H2下反应溅射制备Al掺杂Zn O(AZO)薄膜。通过干涉显微镜、XRD、Hall效应测试仪、紫外-可见分光光度计研究了Ts以及O2和H2流量对薄膜结构及透明导电性能的影响。结果发现,随O2流量增加,两种Ts下制备的AZO薄膜保持(002)择优取向,薄膜中压应力呈下降的趋势,而薄膜结晶度趋向于先增加后略有下降。薄膜的导电性能随O2流量增加呈逐渐增强的趋势。当O2流量高于一定值时,薄膜可以获得较高的可见光透过率,因此达到较高的品质因子。当Ts从150℃增加到300℃,薄膜的压应力降低,结晶度提高,但导电性未见明显提高。另外,薄膜禁带宽度主要由薄膜中压应力决定。与Ar+O2下制备的AZO薄膜相比,Ar+H2气氛下制备的薄膜基本上为非晶态,其导电性能差,而可见光透过率较高、禁带宽度较大。
Different from usually used metal or oxide target,Zn/Zn O mixture with surface attached with Al strips( Al@ Zn/Zn O) was used as target in this paper. With this target,Al-doped Zn O( AZO) thin films were prepared by magnetron sputtering under atmosphere of Ar + O2 and Ar + H2 at substrate temperature( Ts) of 150 ℃ and 300 ℃. The effects of Tsand reactive gas( O2 or H2) flux on the structure and transparent conductive properties of the films were investigated by interference microscope,XRD,Hall effect measurement system and UV-Vis spectrophotometer. When the deposition atmosphere is Ar + O2,the results indicate that the AZO films deposited at both Tskeep( 002) preferred orientation,the compressive stress in the films tends to decrease,and the film crystallinity tends to first improve and then slightly degrade with increasing O2 flux. The conductive properties of the films trend to improve as O2 flux increases. When O2 flux is above a certain value,the films can be achieved with higher visible light transmittance,and thus the films with higher FOM are obtained. As Tsincreases from 150 ℃ to 300℃,the compressive stress decreases,film crystallinity improves,but the conductivity has not obvious change. It is found that the bandgap( Eg) of AZO films is mainly due to their compressive stress. When the deposition atmosphere is Ar + H2,most films are amorphous,and the films show poorer conductivity,higher visible light transmittance,and wider bandgap compared with the films deposited under Ar + O2.
Different from usually used metal or oxide target,Zn/Zn O mixture with surface attached with Al strips( Al@ Zn/Zn O) was used as target in this paper. With this target,Al-doped Zn O( AZO) thin films were prepared by magnetron sputtering under atmosphere of Ar + O2 and Ar + H2 at substrate temperature( Ts) of 150 ℃ and 300 ℃. The effects of Tsand reactive gas( O2 or H2) flux on the structure and transparent conductive properties of the films were investigated by interference microscope,XRD,Hall effect measurement system and UV-Vis spectrophotometer. When the deposition atmosphere is Ar + O2,the results indicate that the AZO films deposited at both Tskeep( 002) preferred orientation,the compressive stress in the films tends to decrease,and the film crystallinity tends to first improve and then slightly degrade with increasing O2 flux. The conductive properties of the films trend to improve as O2 flux increases. When O2 flux is above a certain value,the films can be achieved with higher visible light transmittance,and thus the films with higher FOM are obtained. As Tsincreases from 150 ℃ to 300℃,the compressive stress decreases,film crystallinity improves,but the conductivity has not obvious change. It is found that the bandgap( Eg) of AZO films is mainly due to their compressive stress. When the deposition atmosphere is Ar + H2,most films are amorphous,and the films show poorer conductivity,higher visible light transmittance,and wider bandgap compared with the films deposited under Ar + O2.
引文
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[11]Ding J J,Chen H X,Ma S Y.The Al-doping and Post-annealing Treatment Effects on The Structural and Optical Properties of Zn O:Al Thin Films Deposited on Si Substrate[J].Applied Surface Science.2010,256(13):4304-4309.
[12]Okuda S,Matsuo T,Chiba H,et al.Conductive and Transparent V-doped Zn O Thin Films Grown by Radio Frequency Magnetron Sputtering[J].Thin Solid Films,2014,557:197-202.
[13]谢挺,祝柏林,杨玉婷,等.反应溅射法制备高透明导电Zn O薄膜的研究[J].人工晶体学报,2016,45(3):711-717.
[14]Wang F H,Yang T H.Effect of Hydrogen Doping on The Properties of Al and F Co-doped Zn O Films for Thin Film Silicon Solar Cell Applications[J].Thin Solid Films,2016,605:64-72.
[15]Hasuike N,Nishio K,Kisoda K,et al.Room Temperature Growth of Al-Doped Zn O Thin Films by Reactive DC Sputtering Technique with Metallic Target[J].Japanese Journal of Applied Physics,2013,52(1S):01AC09-4.
[16]Murali B,Parui J,Madhuri M,et al.An insight to The Low Temperature Conduction Mechanism of C-axis Grown Al-doped Zn O,A Widely Used Transparent Conducting Oxide[J].Journal of Physics D-Applied Physics,2015,48(1):015301-015315.
[17]Cornelius S,Vinnichenko M.Al in Zn O-From Doping to Alloying:An Investigation of Al Electrical Activation in Relation to Structure and Charge Transport Limits[J].Thin Solid Films,2016,605:20-29.
[18]Bose S,Arokiyadoss R,Bhargav P B,et al.Modification of Surface Morphology of Sputtered AZO Films with The Variation of The Oxygen[J].Materials Science in Semiconductor Processing,2018,79:135-143.
[19]Guillen C,Herrero J.Optical,Electrical and Structural Characteristics of Al:Zn O Thin Films with Various Thicknesses Deposited by DC Sputtering at Room Temperature and Annealed in Air or Vacuum[J].Vacuum,2010,84(7):924-929.
[20]Zhu B L,Zhao X Z,Xu S,et al.Oxygen Pressure Dependence of Structure and Properties for Zn O Films Deposited on Amorphous Glass Substrates by Pulsed Laser Deposition[J].Japanese Journal of Applied Physics,2008,47(4A):2225-2229.
[21]Yim K,Lee C.Optical Properties of Al-doped Zn O Thin Films Deposited by Two Different Sputtering Methods[J].Crystal Research and Technology,2006,41(12):1198-1202.
[22]Zhu B L,Zhu S J,Wang J,et al.Thickness Effect on Structure and Properties of ZAO Thin Films by RF Magnetron Sputtering at Different Substrate Temperatures[J].Physica E,2011,43(9):1738-1745.
[23]Mohanty B C,Jo Y H,Yeon D H,et al.Stress-induced Anomalous Shift of Optical Band Gap in Zn O:Al Thin Films[J].Applied Physics Letters,2009,95(6):062103-062105.
[24]Tan S T,Chen B J,Sun X W,et al.Blueshift of Optical Band Gap in Zn O Thin Films Grown by Metal-organic Chemical-vapor Deposition[J].Journal of Applied Physics,2005,98(1):013505-013509.
[25]Haacke G.New Figure of Merit for Transparent Conductors[J].Journal of Applied Physics,1976,47(9):4086-4089.
[2]刘超英,左岩,许杰.掺铝氧化锌透明导电膜的研究进展[J].材料导报:综述篇,2010,24(10):126-131.
[3]Alonso-Alvarez D,Llin L F,Mellor A,et al.ITO and AZO Films for Low Emissivity Coatings in Hybrid Photovoltaic-thermal Applications[J].Solar Energy,2017,155:82-92.
[4]陈光羽,何延如,雷志芳,等.AZO薄膜刻蚀形貌优化及其在硅基薄膜双结太阳能电池中的应用[J].人工晶体学报,2012,41(5):1270-1275.
[5]Mickan M,Helmersson U,Horwat D.Effect of Substrate Temperature on The Deposition of Al-doped Zn O Thin Films Using High Power Impulse Magnetron Sputtering[J].Surface&Coatings Technology,2018,347:245-251.
[6]Proost J,Henry F,Tuyaerts R,et al.Effect of Internal Stress on The Electro-optical Behaviour of Al-doped Zn O Transparent Conductive Thin Films[J].Journal of Applied Physics,2016,120(7):075308-075318.
[7]Sun L R,Grant J T,Jones J G,et al.Tailoring Electrical and Optical Properties of Al-doped Zn O Thin Films Grown at Room Temperature by Reactive Magnetron Co-sputtering:From Band Gap to Near Infrared[J].Optical Materials,2018,84:146-157.
[8]Gurbuz O,Guner S.Role of Annealing Temperature on Electrical and Optical Properties of Al-doped Zn O Thin Films[J].Ceramics International,2015,41(3):3968-3974.
[9]Treharne R E,Hutchings K,Lamb D A,et al.Combinatorial Optimization of Al-doped Zn O Films for Thin-film Photovoltaics[J].Journal of Physics D-Applied Physics,2012,45(33):335102-335109.
[10]Gil-Rostra J,Cano M,Pedrosa J M,et al.Electrochromic Behavior of Wx Siy Oz Thin Films Prepared by Reactive Magnetron Sputtering at Normal and Glancing Angles[J].ACS Applied Materials&Interfaces,2012,4(2):628-638.
[11]Ding J J,Chen H X,Ma S Y.The Al-doping and Post-annealing Treatment Effects on The Structural and Optical Properties of Zn O:Al Thin Films Deposited on Si Substrate[J].Applied Surface Science.2010,256(13):4304-4309.
[12]Okuda S,Matsuo T,Chiba H,et al.Conductive and Transparent V-doped Zn O Thin Films Grown by Radio Frequency Magnetron Sputtering[J].Thin Solid Films,2014,557:197-202.
[13]谢挺,祝柏林,杨玉婷,等.反应溅射法制备高透明导电Zn O薄膜的研究[J].人工晶体学报,2016,45(3):711-717.
[14]Wang F H,Yang T H.Effect of Hydrogen Doping on The Properties of Al and F Co-doped Zn O Films for Thin Film Silicon Solar Cell Applications[J].Thin Solid Films,2016,605:64-72.
[15]Hasuike N,Nishio K,Kisoda K,et al.Room Temperature Growth of Al-Doped Zn O Thin Films by Reactive DC Sputtering Technique with Metallic Target[J].Japanese Journal of Applied Physics,2013,52(1S):01AC09-4.
[16]Murali B,Parui J,Madhuri M,et al.An insight to The Low Temperature Conduction Mechanism of C-axis Grown Al-doped Zn O,A Widely Used Transparent Conducting Oxide[J].Journal of Physics D-Applied Physics,2015,48(1):015301-015315.
[17]Cornelius S,Vinnichenko M.Al in Zn O-From Doping to Alloying:An Investigation of Al Electrical Activation in Relation to Structure and Charge Transport Limits[J].Thin Solid Films,2016,605:20-29.
[18]Bose S,Arokiyadoss R,Bhargav P B,et al.Modification of Surface Morphology of Sputtered AZO Films with The Variation of The Oxygen[J].Materials Science in Semiconductor Processing,2018,79:135-143.
[19]Guillen C,Herrero J.Optical,Electrical and Structural Characteristics of Al:Zn O Thin Films with Various Thicknesses Deposited by DC Sputtering at Room Temperature and Annealed in Air or Vacuum[J].Vacuum,2010,84(7):924-929.
[20]Zhu B L,Zhao X Z,Xu S,et al.Oxygen Pressure Dependence of Structure and Properties for Zn O Films Deposited on Amorphous Glass Substrates by Pulsed Laser Deposition[J].Japanese Journal of Applied Physics,2008,47(4A):2225-2229.
[21]Yim K,Lee C.Optical Properties of Al-doped Zn O Thin Films Deposited by Two Different Sputtering Methods[J].Crystal Research and Technology,2006,41(12):1198-1202.
[22]Zhu B L,Zhu S J,Wang J,et al.Thickness Effect on Structure and Properties of ZAO Thin Films by RF Magnetron Sputtering at Different Substrate Temperatures[J].Physica E,2011,43(9):1738-1745.
[23]Mohanty B C,Jo Y H,Yeon D H,et al.Stress-induced Anomalous Shift of Optical Band Gap in Zn O:Al Thin Films[J].Applied Physics Letters,2009,95(6):062103-062105.
[24]Tan S T,Chen B J,Sun X W,et al.Blueshift of Optical Band Gap in Zn O Thin Films Grown by Metal-organic Chemical-vapor Deposition[J].Journal of Applied Physics,2005,98(1):013505-013509.
[25]Haacke G.New Figure of Merit for Transparent Conductors[J].Journal of Applied Physics,1976,47(9):4086-4089.