TY - JOUR
T1 - Fabrication of solar cell with stacked Ge islands for enhanced absorption in the infrared regime
AU - Usami, N.
AU - Alguno, A.
AU - Sawano, K.
AU - Ujihara, T.
AU - Fujiwara, K.
AU - Sazaki, G.
AU - Shiraki, Y.
AU - Nakajima, K.
N1 - Funding Information:
The authors would like to acknowledge R. Shimokawa, A. Yamamoto, A. Hashimoto, S. Koh and W. Pan for fruitful discussions. This work was in part supported by NEDO and Grants-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology.
PY - 2004/3/22
Y1 - 2004/3/22
N2 - We fabricated Si-based solar cell with stacked Ge islands grown via the Stranski-Krastanov growth mode in the intrinsic layer of pin diodes. The onset of the external quantum efficiency in the near infrared regime was extended up to approximately 1.4 μm for the solar cells with stacked Ge islands. The quantum efficiency was found to increase with increasing number of stacking, showing that a part of electron-hole pairs generated within Ge islands was separated by the internal electric field and contributed to the photocurrent. Increase of the processing temperature for the impurity diffusion was found to bring blue-shift of the band gap through the intermixing of Si and Ge as well as the deformation of Ge islands. Therefore, low-temperature process was suggested to be necessary for further enhancement of quantum efficiency in the near infrared regime.
AB - We fabricated Si-based solar cell with stacked Ge islands grown via the Stranski-Krastanov growth mode in the intrinsic layer of pin diodes. The onset of the external quantum efficiency in the near infrared regime was extended up to approximately 1.4 μm for the solar cells with stacked Ge islands. The quantum efficiency was found to increase with increasing number of stacking, showing that a part of electron-hole pairs generated within Ge islands was separated by the internal electric field and contributed to the photocurrent. Increase of the processing temperature for the impurity diffusion was found to bring blue-shift of the band gap through the intermixing of Si and Ge as well as the deformation of Ge islands. Therefore, low-temperature process was suggested to be necessary for further enhancement of quantum efficiency in the near infrared regime.
KW - Ge islands
KW - Molecular beam epitaxy
KW - Solar cell
KW - Stranski-Krastanov growth mode
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U2 - 10.1016/j.tsf.2003.11.027
DO - 10.1016/j.tsf.2003.11.027
M3 - Conference article
AN - SCOPUS:17644448859
SN - 0040-6090
VL - 451-452
SP - 604
EP - 607
JO - Thin Solid Films
JF - Thin Solid Films
T2 - Proceedings of Symposium D on Thin Film and Nano-Structured
Y2 - 10 June 2003 through 13 June 2003
ER -