박막 태양전지용 투명 전극을 위한 Ga 도핑된 ZnO의 RF 전력에 따른 구조 및 전기 특성 변화 = Effect of RF Power on Structural and Electrical Properties of Ga-Doped ZnO for Transparent Electrode of Thin Film Solar Cells

다국어 초록 (Multilingual Abstract)

We have investigated the structural and electrical properties of Ga-doped ZnO (GZO) thin films deposited by an RF magnetron sputtering at various RF powers from 50 to 90W. All the GZO thin films are grown as a hexagonal wurtzite phase with highly c-axis preferred parameters. The structural and electrical properties are strongly related to the RF power. The grain size increases as the RF power increases since the columnar growth of GZO thin film is enhanced at an elevated RF power. This result means that the crystallinity of GZO is improved as the RF power increases. The resistivity of GZO rapidly decreases as the RF power increases up to 70 W and saturates to 90W. In contrast, the electron concentration of GZO increases as the RF power increases up to 70 W and saturates to 90W. GZO thin film shows the lowest resistivity of $2.2{\times}10^{-4}{\Omega}cm$ and the highest electron concentration of $1.7{\times}10^{21}cm^{-3}$ at 90W. The mobility of GZO increases as the RF power increases since the grain boundary scattering decreases due to the reduced density of the grain boundary at a high RF power. The transmittance of GZO thin films in the visible range is above 90%. GZO is a feasible transparent electrode for application as a transparent electrode for thin film solar cells.

참고문헌 (Reference)

1 J. F. Wager, 300 : 1245-, 2003

2 E. Fortunato, 92 : 1605-, 2008

3 B. -H. Choi, 2 (2): 360-, 1992

4 X. Yu, 274 : 474-, 2005

5 A. Martin, 151 : 289-, 2002

6 H. J. Ko, 77 : 3761-, 2000

7 K. C. Lai, 94 : 397-, 2010

8 K. Vanheusden, 68 : 403-, 1996

9 Y. Matsumoto, 67 : 6538-, 1990

10 S. W. Shin, 10 : S274-, 2010

11 J. P. Wiff, 63 : 2470-, 2009

12 Q. B. Ma, 82 : 9-, 2007

13 J. F. Chang, 386 : 79-, 2001

14 J. Ma, 357 : 98-, 1999

15 K. Y. Cheong, 410 : 142-, 2002

16 김병국, "산소플라즈마 전처리된 Polyethylene Naphthalate 기판 위에 증착된 ZnO:Ga 투명전도막의 특성" 한국재료학회 20 (20): 175-180, 2010

17 이지수, "RF 마그네트론 스퍼터링 법으로 유리 기판 위에 성장 시킨 Ga 도핑된 ZnO 박막의 열처리에 따른 구조적, 광학적 특성 평가" 한국진공학회 17 (17): 23-27, 2008

18 "J. Narayan" 102 : 023501-, 2007

19 B. D. Cullity, "Elements of Z-ray Diffraction" Addison-Wesley 99-, 1978