■ Example of research topics ■
Substrate reuse with Epitaxial Lift-Off for low-cost solar cell applications
T. Nakata, N. Miyashita (Okada Lab.), K. Watanabe, H. Sodabanlu, and M. Sugiyama, Y. Okada (Okada Lab.)
The III-V compound semiconductors have an advantage of integrating the multi-junction solar cells yielding record efficiencies. However, these high efficiency solar cells have not been used for terrestrial applications because of the high material cost. After the epitaxial crystal growth, only the device layer is necessary for a solar cell, and hence by reusing the expensive substrates we can achieve cost reduction. The epitaxial lift-off (ELO) is known as a major substrate reuse method. The ELO process is based on the selective etching of an AlAs release layer, which enables the lift-off of a thin film solar cell and the reuse of the substrate. In this research, we are investigating the separation process, the device fabrication process and the substrate cleaning process for the industrial application of the substrate reuse.
Fig. Concept of Epitaxial Lift-off (ELO).