Effect of deposited temperatures of the buffer layer on the band offset of CZTS/In_2S_3 heterostructure and its solar cell performance
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摘要
The effect of the deposition temperature of the buffer layer In_2S_3 on the band alignment of CZTS/In_2S_3 heterostructures and the solar cell performance have been investigated.The In_2S_3 films are prepared by thermal evaporation method at temperatures of 30,100,150,and 200 ℃,respectively.By using x-ray photoelectron spectroscopy(XPS),the valence band offsets(VBO) are determined to be-0.28 ±0.1,-0.28 ±0.1,-0.34 ±0.1,and-0.42 ±0.1 eV for the CZTS/In_2S_3heterostructures deposited at 30,100,150,and 200 ℃,respectively,and the corresponding conduction band offsets(CBO)are found to be 0.3 ±0.1,0.41 ±0.1,0.22±0.1,and 0.01 ±0.1 eV,respectively.The XPS study also reveals that interdiffusion of In and Cu occurs at the interface of the heterostructures,which is especially serious at 200 ℃ leading to large amount of interface defects or the formation of CuInS_2 phase at the interface.The CZTS solar cell with the buffer layer In_2S_3 deposited at 150 ℃ shows the best performance due to the proper CBO value at the heterostructure interface and the improved crystal quality of In_2S_3 film induced by the appropriate deposition temperature.The device prepared at 100 ℃presents the poorest performance owing to too high a value of CBO.It is demonstrated that the deposition temperature is a crucial parameter to control the quality of the solar cells.
The effect of the deposition temperature of the buffer layer In_2S_3 on the band alignment of CZTS/In_2S_3 heterostructures and the solar cell performance have been investigated.The In_2S_3 films are prepared by thermal evaporation method at temperatures of 30,100,150,and 200 ℃,respectively.By using x-ray photoelectron spectroscopy(XPS),the valence band offsets(VBO) are determined to be-0.28 ±0.1,-0.28 ±0.1,-0.34 ±0.1,and-0.42 ±0.1 eV for the CZTS/In_2S_3heterostructures deposited at 30,100,150,and 200 ℃,respectively,and the corresponding conduction band offsets(CBO)are found to be 0.3 ±0.1,0.41 ±0.1,0.22±0.1,and 0.01 ±0.1 eV,respectively.The XPS study also reveals that interdiffusion of In and Cu occurs at the interface of the heterostructures,which is especially serious at 200 ℃ leading to large amount of interface defects or the formation of CuInS_2 phase at the interface.The CZTS solar cell with the buffer layer In_2S_3 deposited at 150 ℃ shows the best performance due to the proper CBO value at the heterostructure interface and the improved crystal quality of In_2S_3 film induced by the appropriate deposition temperature.The device prepared at 100 ℃presents the poorest performance owing to too high a value of CBO.It is demonstrated that the deposition temperature is a crucial parameter to control the quality of the solar cells.
The effect of the deposition temperature of the buffer layer In_2S_3 on the band alignment of CZTS/In_2S_3 heterostructures and the solar cell performance have been investigated.The In_2S_3 films are prepared by thermal evaporation method at temperatures of 30,100,150,and 200 ℃,respectively.By using x-ray photoelectron spectroscopy(XPS),the valence band offsets(VBO) are determined to be-0.28 ±0.1,-0.28 ±0.1,-0.34 ±0.1,and-0.42 ±0.1 eV for the CZTS/In_2S_3heterostructures deposited at 30,100,150,and 200 ℃,respectively,and the corresponding conduction band offsets(CBO)are found to be 0.3 ±0.1,0.41 ±0.1,0.22±0.1,and 0.01 ±0.1 eV,respectively.The XPS study also reveals that interdiffusion of In and Cu occurs at the interface of the heterostructures,which is especially serious at 200 ℃ leading to large amount of interface defects or the formation of CuInS_2 phase at the interface.The CZTS solar cell with the buffer layer In_2S_3 deposited at 150 ℃ shows the best performance due to the proper CBO value at the heterostructure interface and the improved crystal quality of In_2S_3 film induced by the appropriate deposition temperature.The device prepared at 100 ℃presents the poorest performance owing to too high a value of CBO.It is demonstrated that the deposition temperature is a crucial parameter to control the quality of the solar cells.
引文
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[14]Zhou X,Meng W,Dong C,Liu C,Qiu Z,Qi J,Chen J and Wang M2015 RSC Adv.5 90217
[15]Barreau N 2009 Sol.Energy 83 363
[16]Zheng Z M,Yu J L,Cheng S Y,Lai Y F,Zheng Q and Pan D M 2016J.Mater.Sci.27 5810
[17]Gall S,Barreau N,Harel S,Bernede J C and Kessler J 2005 Thin Solid Films 480 138
[18]Minemoto T,Matsui T,Takakura H,Hamakawa Y,Negami T,Hashimoto Y,Uenoyama T and Kitagawa M 2001 Sol.Energy Mater.Sol.Cells 67 83
[2]Katagiri H,Jimbo K,Maw W S,Oishi K,Yamazaki M,Araki H and Takeuchi A 2009 Thin Solid Films 517 2455
[3]Paier J,Asahi R,Nagoya A and Kresse G 2009 Phys.Rev.B 79 115126
[4]Santoni A,Biccari F,Malerba C,Valentini M,Chierchia R and Mittiga A 2013 J.Phys.D:Appl.Phys.46 175101
[5]Barkhouse D A R,Haight R,Sakai N,Hiroi H,Sugimoto H and Mitzi D B 2012 Appl.Phys.Lett.100 193904
[6]Yan C,Liu F Y,Song N,Ng B K,Stride J A,Tadich A and Hao X J2014 Appl.Phys.Lett.104 173901
[7]Rajeshmon V G,Poornima N,Kartha C S and Vijayakumar K P 2013J.Alloys Compd.553 239
[8]Lin L Y,Yu J L,Cheng S Y,Lu P M,Lai Y F,Lin S L and Zhao P Y2014 Appl.Phys.A-Mater.Sci.Process.116 2173
[9]Siol S,Dhakal T P,Gudavalli G S,Rajbhandari P P,De Hart C,Baranowski L L and Zakutayev A 2016 ACS Appl.Mater.Interfaces 8 14004
[10]Long B,Shuying Cheng S Y,Qiao Zheng Q,Jinling Yu J L and Hongjie Jia H J 2016 Mater.Res.Bull.73 140
[11]Kraut E A,Grant R W,Waldrop J W and Kowalczyk S P 1980 Phys.Rev.Lett.44 1620
[12]Anderson R L 1962 Solid State Electron.5 341
[13]Bernede J C,Barreau N,Marsillac S and Assmann L 2002 Appl.Surf.Sci.195 222
[14]Zhou X,Meng W,Dong C,Liu C,Qiu Z,Qi J,Chen J and Wang M2015 RSC Adv.5 90217
[15]Barreau N 2009 Sol.Energy 83 363
[16]Zheng Z M,Yu J L,Cheng S Y,Lai Y F,Zheng Q and Pan D M 2016J.Mater.Sci.27 5810
[17]Gall S,Barreau N,Harel S,Bernede J C and Kessler J 2005 Thin Solid Films 480 138
[18]Minemoto T,Matsui T,Takakura H,Hamakawa Y,Negami T,Hashimoto Y,Uenoyama T and Kitagawa M 2001 Sol.Energy Mater.Sol.Cells 67 83