Growth of $CuGaSe_2$ single crystal thin film for solar cell development and its solar cell application

태양 전지용 $CuGaSe_2$ 단결정 박막 성장과 태양전지로의 응용

  • Published : 2005.12.31

Abstract

Single crystal $CuGaSe_2$ layers were grown on thoroughly etched semi-insulating CaAs(100) substrate at $450^{\circ}C$ with hot wall epitaxy (HWE) system by evaporating $CuGaSe_2$ source at $610^{\circ}C$. The crystalline structure of the single crystal thin films was investigated by the photoluminescence (PL) and double crystal X-ray diffraction (DCXD). The carrier density and mobility of single crystal $CuGaSe_2$ thin films measured with Hall effect by Van der Pauw method are $4.87{\times}10^{17}cm^{-3}$ and $129cm^2/V{\cdot}s$ at 293 K, respectively. The temperature dependence of the energy band gap of the $CuGaSe_2$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g(T)=1.7998eV-(8.7489{\times}10^{-4}eV/K)T^2/(T+335K)$. The voltage, current density of maxiumun power, fill factor, and conversion, efficiency of $n-CdS/p-CuGaSe_2$, heterojunction solar cells under $80mW/cm^2$ illumination were found to be 0.41 V, $21.8mA/cm^2$, 0.75 and 11.17%, respectively.

[ $CuGaSe_2$ ] 단결정 박막은 수평 전기로에서 합성한 $CuGaSe_2$ 다결정을 증발원으로하여, hot wall epitaxy(HWE) 방법으로 증발원과 기판(반절연성 GaAs(100))의 온도를 각각 $610^{\circ}C,\;450^{\circ}C$로 고정하여 단결정 박막을 성장하였다. 이때 단결정 박막의 결정성은 광발광 스펙트럼(PL)과 이중결정 X-선 요동곡선 (DCRC)으로부터 구하였다. Hall 효과는 Van der Pauw 방법에 의해 측정되었으며, 293 K에서 운반자 농도와 이동도는 각각 $4.87{\times}10^{17}/cm^3,\;129cm^2/V{\cdot}s$였다. $n-Cds/p-CuGaSe_2$ 합 태양전지에 $80mW/cm^2$의 광을 조사시켜 최대 출력점에서 전압은 0.41 V, 전류밀도는 $21.8mA/cm^2$였고, fill factor는 0.75 그리고 태양전지 전력변환 효율은 11.17% 였다.

Keywords

References

  1. W. Gebicki, J. Filipowicz and R. Bacewicz, 'Raman scattering in novel $CuGaSe_2$ crystals', J. Phys. Condens. Matter 8 (1996) 8695 https://doi.org/10.1088/0953-8984/8/44/018
  2. J. E. Kim, H. Y. Park, S. G. Lee and J. Y. Lee, 'Photoacoustic spectra of $CuGaSe_2$', New Physics 28(4) (1998) 515
  3. L. Kronik, L. Bursten and M. Leiboritch, 'Band diagram of the polycrystalline CdS/CuGa(In)Se heterojunction', Appl. Phys. Lett. 67(10) (1995) 1405 https://doi.org/10.1063/1.114508
  4. N. Nadenau, U. Rau and A. Jasenek, 'Electronic properties of $CuGaSe_2$-based heterojunction Solar cells. Part I. transport analysis', J. Appl. Phys. 87(1) (2000) 584
  5. S. Endo and T. Irizo, 'LED properties of $CuGaSe_2$ single crystal', J. Phys. Chem. Solids 37 (1971) 201 https://doi.org/10.1016/0022-3697(76)90162-1
  6. E. Grill, M. Uxxi and A.V. Moskalonov, 'Photoluminescience and photocondutivity measurements on $CuGaSe_2$', J. Phys. C: Solid State Phys. 114 (1978) 2361
  7. H. Nakanish, 'Study of the band edge in $CuGaSe_2$ by photovoltaic effect', Jpn. J. Appl. Phys. 19 (1980) 103 https://doi.org/10.1143/JJAP.19.103
  8. S. Charbonneau and E. Fortin, 'Sturation photoconductivity in $CuGaSe_2$', Phys. Rew. B 31(4) (1985) 2326 https://doi.org/10.1103/PhysRevB.31.2326
  9. H. Nakanish, 'Study of the band edge in $CuGaSe_2$ by photovoltaic effect', Jpn. J. Appl. Phys. 19 (1980) 103 https://doi.org/10.1143/JJAP.19.103
  10. S. Charbonneau and E. Fortin, 'Sturation photoconductivity in $CuGaSe_2$', Phys. Rew. B 31(4) (1985) 2326 https://doi.org/10.1103/PhysRevB.31.2326
  11. L. Lerner, '$CuGaSe_2$ and $AgInSe_2$, : Preparation and property of single crystal', J. Phys. Chem. Solids Zn (1966) 1
  12. K.J. Hong and T.S. Jeong, 'The characterization of ZnSe/GaAs epilayers grown by hot wall epitaxy', J. Cryst. Growth 172 (1997) 89 https://doi.org/10.1016/S0022-0248(96)00725-7
  13. A. Shankat and R.D. Singh, 'Tetragonal distortion for $A^{I}{\cdot}B^{II}{\cdot}C_2^{III}$ chalcopyrite compounds', J. Phys. Chem. Solid. 39 (1978) 1269 https://doi.org/10.1016/0022-3697(78)90123-3
  14. B.D. Cullity, Elements of X-ray Diffractions, (Addson-Welsey, 1985) Chap.11
  15. R.B. Nartine, 'Photoluminescience and photocondutivity measurements on $CuGaSe_2$', Phil. Mag. 46 (1955) 831 https://doi.org/10.1080/14786440808561235
  16. Elizabeth A. Wood, Crystal Orientation manual, Columbia university press (1963)
  17. H. Fujita, 'Electron radition damage in cadium-selenide crystal at liquid-helium temperrature', J. Phys. Soc., Jpn. 20 (1965) 109
  18. V.P. Varshni, 'Far-infrared optical absorption of $Fe^{2+}$ in ZnSe', Physica 34 (1967) 149
  19. S.M. Sze, 'Semiconductor devices: physics and technology', Wily. Chap.3 (1998)