周期性结构Mo背电极的设计及其陷光特性研究与应用
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摘要
为了改善金属钼(Mo)电极的光学特性,采用类桑拿法通过聚苯乙烯小球自组装制备了具有周期性结构的Mo电极,通过控制钼的沉积厚度和小球的刻蚀时间来获得具有不同高度和周期的衬底结构,并研究了其对周期性Mo衬底光学特性的影响。实验结果表明:周期性结构衬底显著提高了长波区域(>1 100nm)的反射,尤其当铜锌锡硒(CZTSe)吸收层厚度减薄至0.5μm时,为了进一步增加光吸收,通过在CZTSe薄膜表面引入金字塔形貌的氧化锌,与周期性衬底形成了光学陷阱结构,增加了CZTSe光吸收。该结果对超薄化合物电池的研究具有一定的指导作用。
To improve the optical property of molybdenum(Mo)electrodes,periodical textured Mo electrodes by self-assembling monolayer and hexagonal closely-arranged polystyrene(PS)spheres using a Sauna-like method were fabricated and modulated in this study.By modulating the thicknesses of Mo electrodes and the etching times of PS spheres,the substrate morphologies with various height and period features were effectively acquired and their effects on optical properties of periodical textured Mo electrodes were simultaneously investigated.Experimental results show that the long-wavelength reflection(>1 100nm)can be significantly improved with our proposed periodical textured Mo electrodes,thereby enhancing the light absorption in Copper Zinc Tin Selenium(CZTSe)absorbers,especially in ultrathin ones(0.5μm).By further introducing metal-organic chemical vapor deposition(MOCVD)prepared pyramid-like zinc oxide(ZnO)films on CZTSe absorbers to form a light trapping architecture with the periodical textured Mo substrates,we successfully improve the light absorption in CZTSe absorbers further.Our proposed periodical textured Mo electrodes and the light trapping architecture may pave the way for the device design of ultrathin solar cells,such as CIGS et al.
To improve the optical property of molybdenum(Mo)electrodes,periodical textured Mo electrodes by self-assembling monolayer and hexagonal closely-arranged polystyrene(PS)spheres using a Sauna-like method were fabricated and modulated in this study.By modulating the thicknesses of Mo electrodes and the etching times of PS spheres,the substrate morphologies with various height and period features were effectively acquired and their effects on optical properties of periodical textured Mo electrodes were simultaneously investigated.Experimental results show that the long-wavelength reflection(>1 100nm)can be significantly improved with our proposed periodical textured Mo electrodes,thereby enhancing the light absorption in Copper Zinc Tin Selenium(CZTSe)absorbers,especially in ultrathin ones(0.5μm).By further introducing metal-organic chemical vapor deposition(MOCVD)prepared pyramid-like zinc oxide(ZnO)films on CZTSe absorbers to form a light trapping architecture with the periodical textured Mo substrates,we successfully improve the light absorption in CZTSe absorbers further.Our proposed periodical textured Mo electrodes and the light trapping architecture may pave the way for the device design of ultrathin solar cells,such as CIGS et al.
引文
[1] Ramanathan K,Noufi R,To B,et al.Processing and properties of sub-micron CIGS solar cells[C]//2006IEEE 4th World Conference on Photovoltaic Energy Conference.NewYork:IEEE,2006:380-383.
[2] XUE Yuming,XU Chuanming,ZHANG Li,et al.Evolution of(In,Ga)2Se3-Cu rich-In(Ga)rich of CIGS thin films[J].Journal of Optoelectronics·Laser,2008,19(3):349-351.
[3] JIANG Weilong,ZHANG Li,HE Qing,et al.High efficiency Cu(In,Ga)Se2thin-film solar cells doped Na on polyimide substrate[J].Journal of Optoelectronics·Laser,2010,21(2):222-267.
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[6] YOON J H,YOON K H,KIM W M,et al.High-temperature stability of molybdenum(Mo)back contacts for CIGS solar cells:a route towards more robust back contacts[J].Journal of Physics D:Applied Physics,2011,44(42):425302-425309.
[7] WU H M,LIANG S C,LIN Y L,et al.Structure and electrical properties of Mo back contact for Cu(In,Ga)Se2 solar cells[J].Vacuum,2012,86(12):1916-1919.
[8] KHATRI H,MARSILLAC S.The effect of deposition parameters on radiofrequency sputtered molybdenum thin films[J].Journal of Physics:Condensed Matter2008,20(5):055206-055211.
[9] ABOU-RAS D,KOSTORZ G,BREMAUD D,et al.Formation and characterisation of MoSe2for Cu(In,Ga)Se2based solar cells[J].Thin Solid Films,2005,480-481(3):433-438.
[10]HSIAO K J,LIU J D,HSIEH H H,et al.Electrical impact of MoSe2 on CIGS thin-film solar cells[J].Physical Chemistry Chemical Physics,2013,15(41):18174-18178.
[11]YOON J H,SEONG T Y,JEONG J H.Effect of a Mo back contact on Na diffusion in CIGS thin film solar cells[J].Progress in Photovoltaics:Research and Applications,2013,21(1):58-63.
[12]YOON J H,CHO S,KIM W M,et al.Optical analysis of the microstructure of a Mo back contact for Cu(In,Ga)Se2solar cells and its effects on Mo film properties and Na diffusivity[J].Solar Energy Materials and Solar Cells,2011,95(11):2959-2964.
[13]Gifford J.Solar Frontier Hits 22.3%on CIGS Cell[J].Industry and Suppliers,Market and Trends,2015.
[14]GLOECKLER M,SITES J R.Potential of submicrometer thickness Cu(In,Ga)Se[sub 2]solar cells[J].Journal of Applied Physics,2005,98(10):103703-103707.
[15]BOUTTEMY M,TRAN-VAN P,GERARD I,et al.Thinning of CIGS solar cells:Part I:chemical processing in acidic bromine solutions[J].Thin Solid Films,2011,519(21):7207-7211.
[16]JEHL Z,ERFURTH F,NAGHAVI N,et al.Thinning of CIGS solar cells:Part II:cell characterizations[J].Thin Solid Films,2011,519(21):7212-7215.
[17]KO B S,SUNG S J,KIM D H,et al.Effects of annealing on structural and electrical properties of sub-micron thick CIGS films[J].Applied Physics,2013,13:135-139.
[18]CAMPA A,KRC J,MALMSTROM J,et al.The potential of textured front ZnO and flat TCO/metal back contact to improve optical absorption in thin Cu(In,Ga)Se2solar cells[J].Thin Solid Films,2007,515(15):5968-5972.
[19]LONG Fei,MO Shuyi,CHI Shangsen,et al.Progresses of Cu-2ZnSn(S,Se)-4thin film solar cells[J].Semiconductor Optoelectronics,2014,35(2):165-205.(in Chinese)
[20]LIU Bofei,LIANG Xuejiao,LIANG Junhui,et al.Broadband light trapping based on periodically textured ZnO thin films[J].Nanoscale,2015,7(21):9816-9824.
[21]LIANG Xuejiao,LIU Bofei,BAI Lisa,et al.Periodically textured metal electrodes:large-area fabrication,characterization,simulation,and application as efficient back-reflective scattering contact-electrodes for thin-film solar cells[J].Journal of Materials Chemistry A,2014,2(15):13259-13264.
[2] XUE Yuming,XU Chuanming,ZHANG Li,et al.Evolution of(In,Ga)2Se3-Cu rich-In(Ga)rich of CIGS thin films[J].Journal of Optoelectronics·Laser,2008,19(3):349-351.
[3] JIANG Weilong,ZHANG Li,HE Qing,et al.High efficiency Cu(In,Ga)Se2thin-film solar cells doped Na on polyimide substrate[J].Journal of Optoelectronics·Laser,2010,21(2):222-267.
[4] ORGASSA K,SCHOCK H W,WERNER J H.Alternative back contact materials for thin film Cu(In,Ga)Se2solar cells[J].Thin Solid Films,2003,431-432(1):387-391.
[5] BLOSCH P,NISHIWAKI S,JAEGER T,et al.Alternative back contact designs for Cu(In,Ga)Se2solar cells on polyimide foils[J].Thin Solid Films,2013,535(19):220-223.
[6] YOON J H,YOON K H,KIM W M,et al.High-temperature stability of molybdenum(Mo)back contacts for CIGS solar cells:a route towards more robust back contacts[J].Journal of Physics D:Applied Physics,2011,44(42):425302-425309.
[7] WU H M,LIANG S C,LIN Y L,et al.Structure and electrical properties of Mo back contact for Cu(In,Ga)Se2 solar cells[J].Vacuum,2012,86(12):1916-1919.
[8] KHATRI H,MARSILLAC S.The effect of deposition parameters on radiofrequency sputtered molybdenum thin films[J].Journal of Physics:Condensed Matter2008,20(5):055206-055211.
[9] ABOU-RAS D,KOSTORZ G,BREMAUD D,et al.Formation and characterisation of MoSe2for Cu(In,Ga)Se2based solar cells[J].Thin Solid Films,2005,480-481(3):433-438.
[10]HSIAO K J,LIU J D,HSIEH H H,et al.Electrical impact of MoSe2 on CIGS thin-film solar cells[J].Physical Chemistry Chemical Physics,2013,15(41):18174-18178.
[11]YOON J H,SEONG T Y,JEONG J H.Effect of a Mo back contact on Na diffusion in CIGS thin film solar cells[J].Progress in Photovoltaics:Research and Applications,2013,21(1):58-63.
[12]YOON J H,CHO S,KIM W M,et al.Optical analysis of the microstructure of a Mo back contact for Cu(In,Ga)Se2solar cells and its effects on Mo film properties and Na diffusivity[J].Solar Energy Materials and Solar Cells,2011,95(11):2959-2964.
[13]Gifford J.Solar Frontier Hits 22.3%on CIGS Cell[J].Industry and Suppliers,Market and Trends,2015.
[14]GLOECKLER M,SITES J R.Potential of submicrometer thickness Cu(In,Ga)Se[sub 2]solar cells[J].Journal of Applied Physics,2005,98(10):103703-103707.
[15]BOUTTEMY M,TRAN-VAN P,GERARD I,et al.Thinning of CIGS solar cells:Part I:chemical processing in acidic bromine solutions[J].Thin Solid Films,2011,519(21):7207-7211.
[16]JEHL Z,ERFURTH F,NAGHAVI N,et al.Thinning of CIGS solar cells:Part II:cell characterizations[J].Thin Solid Films,2011,519(21):7212-7215.
[17]KO B S,SUNG S J,KIM D H,et al.Effects of annealing on structural and electrical properties of sub-micron thick CIGS films[J].Applied Physics,2013,13:135-139.
[18]CAMPA A,KRC J,MALMSTROM J,et al.The potential of textured front ZnO and flat TCO/metal back contact to improve optical absorption in thin Cu(In,Ga)Se2solar cells[J].Thin Solid Films,2007,515(15):5968-5972.
[19]LONG Fei,MO Shuyi,CHI Shangsen,et al.Progresses of Cu-2ZnSn(S,Se)-4thin film solar cells[J].Semiconductor Optoelectronics,2014,35(2):165-205.(in Chinese)
[20]LIU Bofei,LIANG Xuejiao,LIANG Junhui,et al.Broadband light trapping based on periodically textured ZnO thin films[J].Nanoscale,2015,7(21):9816-9824.
[21]LIANG Xuejiao,LIU Bofei,BAI Lisa,et al.Periodically textured metal electrodes:large-area fabrication,characterization,simulation,and application as efficient back-reflective scattering contact-electrodes for thin-film solar cells[J].Journal of Materials Chemistry A,2014,2(15):13259-13264.