Title: Growth of nanowires by selective-area metalorganic vapor phase epitaxy and their applications

Speaker:  Prof. Junichi Motohisa(Research Center for Integrated Quantum Electronics, Hokkaido University)

Time: Sep5 2009 15:00(PM)

Venue：Institute of Semiconductors,  CAS

　  Abstract:Semiconductor nanowires have stimulated extensive interest in recent years because of their unique properties and potential applications as building blocks for nanoscale electronic and photonic devices. So far, most of the nanowires have been grown by catalyst-assisted vapor-liquid-solid growth mechanism. We have been reporting on the systematically controlled growth of III-V compound semiconductor nanowire arrays by catalyst-free selective area metalorganic vapor phase epitaxy (SA-MOVPE) on partially masked substrates <1-3>. The length, diameter, shape and position of the nanowires were precisely controlled by optimization of the growth conditions and mask patterning. Manipulation of the growth conditions, particularly with a combination of the growth of heterostructures, also enabled us to deliberately define the nanowire growth along either the axial or the radial direction, which has significant potential for the realization of novel nanostructures containing heterostructures. Very recently, we have succeeded in the growth of III-V nanowires on Si <4,5>, opening up a possibility of integration of III-V devices on Si platforms.The grown nanowires are used for realize various kind of devices. To date, we have demonstrated FETs using lay-down nanowires <6>. We also have shown that the nanowires with core-shell heterostrutures exhibits lasing under plused light excitations with specific interference patterns <7>. More recently, the as-grown nanowire arrays are used for photovoltaic devices, which exhibited conversion efficiency of 3.37 % under AM 1.5G irradiation <8>.

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　  <2> P. Mohan et al., 16, 2903 (2005).

　  <3> K. Tomioka et al., J. Cryst. Growth 298, 644 (2007).

　  <4> K. Tomioka et al., Nano Lett. 8, 3475 (2008).

　  <5> K. Tomioka et al., Nanotechnology 20, 145302 (2009).

　  <6> J. Noborisaka et al., Jpn. J. Appl. Phys 46, 7562 (2007).

　  <7> B. Hua et al., Nano Lett. 9, 112 (2009).

　  <8> H. Goto et al., Appl. Phys. Exp. 2, 035004 (2009).