CIGS太阳能电池CuGa和CuGa-碱金属溅射靶的研制

CSC PROPRIETARY Development of CuGa and CuGa-alkali metal sputtering targets for CIGS solar cells Rong-Zhi Chen Ph.D. China Steel Corporation New Materials R&D Dept. 2019.06.04 CSC PROPRIETARY Outline  Introduction  Experimental Procedures  Results and Discussion  Conclusions CSC PROPRIETARY Outline  Introduction  Experimental Procedures  Results and Discussion  Conclusions CSC PROPRIETARY1  Founded ： December 3, 1971  Location： Kaohsiung City, Taiwan  Capital： 35 billion CNY (2018)  Revenue： 92 billion CNY (2018)  Products： Carbon steels, Low alloy steels…  Employee： 10,205 (2019)  R&D Staff： ~ 370 (2019) Company Profile (China Steel Corporation) CSC PROPRIETARY2 Business Fields of CSC Group CSC Group contains 26 subsidiary companies in the field of： Steel Business Engineering Business Industrial Materials Business Trading & Logistics Business Services & Investments Business CSC PROPRIETARY3  Back electrode  Absorber layer ( p-type )  Buffer layer ( n-type )  Transparent electrode Mo T/G CuGa-KF T/G CuGa-NaF T/G CuGa T/G In T/G Si T/G CIGS solar cell structure ➢ All of the above CIGS sputtering targets can be provided by CSC group. CSC PROPRIETARY4 CIGS sputtering targets In CuGa-Na2SeO3CuGa CuGa-NaF CuGa-KF CSC PROPRIETARY5 CIGS sputtering targets Mo Mo CSC PROPRIETARY6 ➢ All of the above CIGS sputtering targets can be provided by CSC group. Post-depositi n treatment (PDT) wi h NaF and KF improv s the junction quality and allows lower optical losses. F. Pianezzi, P. Reinhard, et al., Phys.Chem.Chem.Phys, 16, 8843-8851, 2014 A. Chirilă, P. Reinhard, F. Pianezzi, et al., Nature Materials, 12, 1107-1111, 2013 PDT with alkali metal fluoride CSC PROPRIETARY Outline  Introduction  Experimental Procedures  Results and Discussion  Conclusions CSC PROPRIETARY CuGa pre-alloyed powders Powders mixing Forming & densifying Targets machining Targets evaluating NaF & KF powders Solar cells assembling Efficiency measuring CuInGaSe(S) thin film depositing  Hot Pressing  HIP Experimental procedures 7 CSC PROPRIETARY Outline  Introduction  Experimental Procedures  Results and Discussion  Conclusions CSC PROPRIETARY Ref： US patent No. 20100116341 A1(2010). Cu-Ga phase diagram ➢ The dominate structure of the Cu-30at.%Ga is brittle γ phase (Cu9Ga4). 8 CSC PROPRIETARY PS. CG30-A : 100% Cu-30at.%Ga CG30-B : Cu-35at.%Ga : Cu-15at.%Ga = 75.5 : 24.5 (wt.%) CG30-C : Cu-35at.%Ga : Cu-25at.%Ga = 50 : 50 (wt.%) Cu-30at.%Ga targets Relative density (%) Bending strength (MPa) CG30-A 100 216.3  5.9 CG30-B 100 225.9  7.9 CG30-C 100 418.1  8.4 Bending strength of CuGa T/G ➢ The more CuGa pre-alloyed powders with gallium content below 30 at.% are added, the higher strength of Cu-30at.%Ga target is fabricated. 9 CSC PROPRIETARY10 Microstructure of CuGa T/G (OM) CG30-A (216 MPa) CG30-C (418 MPa) ➢ The difference in the strength of Cu-30at.%Ga target is not related to the grain size of targets after sintering. CSC PROPRIETARY Phase identification of CuGa T/G (XRD) CG30-C : Cu-35at.%Ga : Cu-25at.%Ga = 50 : 50 (wt.%) CG30-B : Cu-35at.%Ga : Cu-15at.%Ga = 75.5 : 24.5 (wt.%) CG30-A : 100% Cu-30at.%Ga ➢ The increase of softer phase (Cu3Ga) with the increasing addition of the low gallium content CuGa powders.11 CSC PROPRIETARY12 200μm Microstructure of CuGa-NaF T/G 200μm Dry miximg Wet mixing (two-stage) NaF ➢ The fair uniform microstructure of CuGa-NaF targets can be obtained by the two-stage wet mixing process. CSC PROPRIETARY13 Microstructure of CuGa-x T/G Cu-30at.%Ga-NaF ➢ The black alkali metal fluoride inclusions (1~2 at.%) are uniformly distributed in the Cu-30at.%Ga matrix. Cu-30at.%Ga-KF 100μm100μm CuGa CuGa CSC PROPRIETARY 300~400 nm 400~540 nm 540~1200 nm EQE spectrum of the CIGS device ➢ External Quantum Efficiency (EQE) is the ratio of the number of charge carriers collected by the solar cell to the number of incident photons shining on the solar cell from outside. 14 CSC PROPRIETARY 300~400 nm 400~540 nm 540~1200 nm EQE spectrum of the CIGS devices ➢ The quantum efficiency of CIGSe-Na/K device (red line) is significantly better than that of CIGSe-Na one (blue line). 15 CSC PROPRIETARY I–V curves & photovoltaic data ➢ The current–voltage curves of CIGSe-Na/K and CIGSe-Na devices are fairly square. ➢ The fill factor (FF) and short-circuit current (Jsc) of CIGSe- Na/K device are higher than those of CIGSe-Na device. Voc (mV) J sc (mA/cm2) FF (%)  (%) CIGS-Na 635 30.43 72.5 14.01 CIGS-Na/K 610 33.68 74.0 15.19 16 CSC PROPRIETARY Outline  Introduction  Experimental Procedures  Results and Discussion  Conclusions CSC PROPRIETARY17 ➢ In the present study, the brittleness and machinability of the Cu-30at.%Ga targets manufactured by using two CuGa prealloyed powders with different gallium ratio can be grearly improved. Conclusions ➢ The fair uniform microstructure of CuGa-alkali metal fluoride targets can be obtained by the two-stage wet mixing process. ➢ The photoelectric conversion efficiency of solar cell with the CIGS absorber layer subjected to selenization and sulfurization is up to 15.19%. CSC PROPRIETARY Thank you Rong-Zhi Chen ( 陈荣志 ) Ph.D. 150250@mail.csc.com.tw