"Si-based Nano-Structures for Energy Applications and Others"

Professor Ching-Fuh Lin, Department of Electrical Engineering National Taiwan University, Taipei, Taiwan

January 27th (Thursday), 2:00pm
Engineering Science Building , Rm 2001

The foreseeable depletion of fossil fuel and the global warming caused by the carbon dioxide had led to the increasing attention of alternative renewable energy and energy saving. Therefore, crystalline Si-PV devices are quickly spreading and LEDs for lighting are very attractive. In this talk, we will mainly discuss the use of Si-based nanostructures for energy applications.

For the solar cells using Si nanowires, we will discuss two major parts: the combination of the Si nanowires with the organic materials to form p-n junction and the technique to form single crystalline Si thin film to lower the material cost. The fabrication of Si-nanowire/PEDOT solar cells is simple in terms of process steps. The device so far demonstrates a power conversion efficiency of 8.05%. On the other hand, the single crystalline Si thin-film is fabricated using two-step etching technique. The film thickness could be from around 5 um to 15 um. For the film of 15 um, the absorption is 99% in the wavelength range of from below 400 nm to 800 nm, then decreases to about 90% at the wavelength 912 nm. The film has very good crystal orientation, almost identical to Si wafer.

For energy saving, GaN LED is expected to play a very important role for its potential of achieving over 200 lm/W. In addition to lighting efficacy, large-area fabrication and low cost are also important. Current GaN LEDs are mainly based on sapphire wafers. To speed up the LED fabrication and reduce the cost, Si-based white-light LEDs are very attractive. Here we will report the special process to grow ZnO nano or micro-rods with very good alignment toward vertical orientation. Because of the good lattice match between ZnO and GaN, those Si-based ZnO rods could enable the fabrication of GaN LEDs based on Si wafer to reduce cost and to promise production on wafers of beyond 6 inches.

Other applications using Si-photonics will also be briefly discussed.

About Professor Ching-Fuh Lin:

Prof. Ching-Fuh Lin obtained the B.S. degree from National Taiwan University in 1983, and the M.S. and Ph.D. degrees from Cornell University, Ithaca, NY, in 1989 and 1993, respectively, all in electrical engineering.

He is now the Chairman of Graduate Institute of Photonics and Optoelectronics and a joint professor in the Graduate Institute of Photonics and Optoelectronics, Graduate Institute of Electronics Engineering, and Department of Electrical Engineering at National Taiwan University. His research interests include single-crystal Si thin-film solar cells, organic-inorganic composite thin-film solar cells and optoelectronic devices, Si-based photonics, and physics in broadband semiconductor lasers and optical amplifiers.

He is currently a Fellow of IEEE, a Fellow of SPIE, Member of Asia-Pacific Academy of Materials, and a member of OSA. He has published over 140 journal papers and more than 300 conference papers and hold over 30 patents. He had obtained the Distinguished Research Award and Class A Research Awards from National Science Council of Taiwan, ROC, and the Outstanding Electrical Engineering Professor Award from the Chinese Institute of Electrical Engineering and many other awards, including the 18th Acer Research Golden Award, 18th Acer Research Excellent Award, 14th Acer Research Excellent Award, Collins Thesis Awards for years of 1998, 2001, 2002, 2004, 2007, 2009, and 2010.

Hosted by: Professor Larry Coldren