Acknowledgement Coworkers: Yi-Chuan Tseng, Yan-Bo Huang Prof. Hsuen-Li Chen (Department of Material Science and Engineering) Monthly discussion with the joint team members from Dr. Ching-Fuh Lin, Dr. Wing-Kit Choi and Dr. Chao-Hsin Wu. This work is supported by International Collaboration Project with Peking University (Grant No. NTU-ICRP- 102R7558). 2
Outline Motivation and Prior Arts Design and Fabrication Experiment Results Discussion Summary 3
Optical fibers are silica based for communication/sensing Pros and Cons Semiconductor devices -- Si based for electronics, III-V for light sources Pros and Cons Semiconductor fibers ?? Many unknowns with expected pros and cons Potential Applications mid-Infrared Nonlinear Silicon photonics Sensing 4 Motivation Sand – abundant supply for making glass fibers and Si chips, a blessing from Heaven to whom we should be grateful.
Research Groups Worldwide Southampton University Clemson University Pen. State University 5
Properties of Semiconductor Fibers Optics Size: a few microns depending on transmission or sensing Low transmission loss Crystalline, smooth interface or surface Doping for light sources Rare earth elements Electronics Size: microwire to nanowire Good conductivity Crystalline better than poly and amorphous Doping for n- and p-type E-O integration: 22nm node and below, placement, etc. 6
Prior Arts 7 Pier J. A. Sazio et al, Southampton University, Science Vol. 311 No. 1583 (2006) fabricated by using HPCVD carrier mobility 1.05 cm 2 /Vs vs. typical Si FET 10^4-10^5 cm 2 /Vs 11mm long, dia. 100um, core 5um relatively easy in control on crystalline direction, roughness and diffusion. loss 3dB/cm
8 P. J. A. Sazio et al, Southampton university, OE Vol. 20 No.4 (2012) John Ballato et al, Clemson university, OE Vol. 16 No.23 (2008) fabricated by using CVD fabricated by using molten core method Prior Arts a few meter long, loss 5~7dB/cm
9 P. J. A. Sazio et al, Southampton university, Nature photonics, Vol. 6 No.174 (2012) Prior Arts amorphous p-n junction Toward useful junction based devices OE conversion with a pulsed laser
10 JLT Vol. 27 No.15 (2009) pure SiO 2 micro fiber Well, Our Prior Arts Uniqueness: several meters long with below nm surface roughness Using conventional SMF as preform
Micro Coil Rings 11 FSR = 270pm Resolution: 5pm Spectrum of 2-ring Coil A typical photograph of an MCR whose gaps between adjacent rings are controlled within 1.5 μm.
Experiment Results optical microscope images c a.Cross section of Si cored fiber b.Lateral view of Si cored fiber c.Lateral view of silicon core Visual inspection
13 Results and Discussion crystalline characterization Chil-Chyuan Kuo, J. Russ. Laser Res., vol. 32, pp. 12 (2011) B.L. Boyce et al., Acta Materialia, vol. 58, pp. 439 (2010) Boundaries can be observed for and poly-Si when FE-SEM is used.
P. Hashemi et al, University of Tehran, Conference of Microelectronics, pp. 326 (2005) Results and Discussion Raman characterization – to know possible causes for crystalline
Summary Long Si-cored silica-clad fibers were made. Their propagation losses were measured, and crystalline properties characterized. 15
Thanks for your attention! Questions? Dreams? 16