Ray LaPierre (McMaster University, Canada)

Nanowire materials and applications

Tilted view scanning electron microscopy (SEM) images, showing examples of nanowires

III-V compound semiconductor nanowires (NWs) are being developed for the next generation of optoelectronic devices such as photodetectors, photovoltaics, betavoltaics and thermoelectrics. The self-assisted vapor-liquid-solid method is now a well-established technique for the growth of III-V NWs on silicon substrates. In this method, an array of holes in a SiO2 film is used for metal droplet formation, which seeds the growth of vertically oriented NWs within a periodic array. The free lateral surfaces of NWs allow elastic relaxation of lattice misfit strain without the generation of dislocations, permitting unique heterostructures and the direct integration of III-V materials on inexpensive silicon substrates. Furthermore, NWs permit high optical absorption due to an optical antenna effect. The optical absorption in NW arrays can exceed that due to a thin film of equivalent thickness, enabling high efficiency NW-based photovoltaic devices. Optical resonances that depend on the NW diameter allow multispectral absorption for infrared camera applications. Some of the challenges associated with NW materials and devices will be illustrated.

Biographical Sketch:

Ray LaPierre

Ray LaPierre obtained a Ph.D. degree in 1997 in the Engineering Physics Department at McMaster University (Hamilton, Ontario, Canada) where he developed molecular beam epitaxy of compound semiconductor alloys for laser diodes in telecom applications. Upon completion of his graduate work, he joined JDS Uniphase (Ottawa, Ontario, Canada) where he developed dielectric coatings for wavelength division multiplexing devices. In 2004, he rejoined McMaster University as an Assistant Professor in the Engineering Physics Department. He is currently Professor and Chair with interests in III-V nanowires, molecular beam epitaxy, and applications in photovoltaics, photodetectors, betavoltaics, thermoelectrics and quantum information processing.  He has over 119 lifetime publications, 57 invited presentations and 179 contributed conference presentations. He is also Editor-in-Chief of the journal Nanotechnology.
Further information related to Dr. LaPierre’s research may be found at this link.


Department of Engineering Physics, McMaster University, Hamilton, Ontario, Canada, L8S4L7
E-mail: lapierr@mcmaster.ca