quantum heterostrucures; growth direction; growth mechanisms; molecular beam epitaxy; nanowires
Dubrovskii Vladimir G., Kim Wonjong, Piazza Valerio, Güniat Lucas, Fontcuberta i Morral Anna (2021), Simultaneous Selective Area Growth of Wurtzite and Zincblende Self-Catalyzed GaAs Nanowires on Silicon, in Nano Letters
, 21(7), 3139-3145.
Kim Wonjong, Güniat Lucas, Fontcuberta i Morral Anna, Piazza Valerio (2021), Doping challenges and pathways to industrial scalability of III–V nanowire arrays, in Applied Physics Reviews
, 8(1), 011304-011304.
Escobar Steinvall Simon, Ghisalberti Lea, Zamani Reza R., Tappy Nicolas, Hage Fredrik S., Stutz Elias Z., Zamani Mahdi, Paul Rajrupa, Leran Jean-Baptiste, Ramasse Quentin M., Craig Carter W., Fontcuberta i Morral Anna (2020), Heterotwin Zn 3 P 2 superlattice nanowires: the role of indium insertion in the superlattice formation mechanism and their optical properties, in Nanoscale
, 12(44), 22534-22540.
Braun Michael R, Güniat Lucas, Fontcuberta I Morral Anna, McIntyre Paul C (2020), In-situ reflectometry to monitor locally-catalyzed initiation and growth of nanowire assemblies, in Nanotechnology
, 31(33), 335703-335703.
Balgarkashi A, Ramanandan S P, Tappy N, Nahra M, Kim W, Güniat L, Friedl M, Morgan N, Dede D, Leran J B, Couteau C, Fontcuberta i Morral A (2020), Facet-driven formation of axial and radial In(Ga)As clusters in GaAs nanowires, in Journal of Optics
, 22(8), 084002-084002.
Friedl Martin, Cerveny Kris, Huang Chunyi, Dede Didem, Samani Mohammad, Hill Megan O., Morgan Nicholas, Kim Wonjong, Güniat Lucas, Segura-Ruiz Jaime, Lauhon Lincoln J., Zumbühl Dominik M., Fontcuberta i Morral Anna (2020), Remote Doping of Scalable Nanowire Branches, in Nano Letters
, 20(5), 3577-3584.
Vukajlovic-Plestina J., Kim W., Ghisalberti L., Varnavides G., Tütüncuoglu G., Potts H., Friedl M., Güniat L., Carter W. C., Dubrovskii V. G., Fontcuberta i Morral A. (2019), Fundamental aspects to localize self-catalyzed III-V nanowires on silicon, in Nature Communications
, 10(1), 869-869.
Jürgensen C, Mikulik D, Kim W, Ghisalberti L, Bernard G, Friedl M, Carter W Craig, Fontcuberta i Morral A, Romero-Gomez P (2019), Growth of nanowire arrays from micron-feature templates, in Nanotechnology
, 30(28), 285302-285302.
Ghisalberti Lea, Potts Heidi, Friedl Martin, Zamani Mahdi, Güniat Lucas, Tütüncüoglu Gözde, Carter W Craig, Morral Anna Fontcuberta i (2019), Questioning liquid droplet stability on nanowire tips: from theory to experiment, in Nanotechnology
, 30(28), 285604-285604.
Güniat Lucas, Caroff Philippe, Fontcuberta i Morral Anna (2019), Vapor Phase Growth of Semiconductor Nanowires: Key Developments and Open Questions, in Chemical Reviews
, 119(15), 8958-8971.
Güniat Lucas, Martí-Sánchez Sara, Garcia Oscar, Boscardin Mégane, Vindice David, Tappy Nicolas, Friedl Martin, Kim Wonjong, Zamani Mahdi, Francaviglia Luca, Balgarkashi Akshay, Leran Jean-Baptiste, Arbiol Jordi, Fontcuberta i Morral Anna (2019), III–V Integration on Si(100): Vertical Nanospades, in ACS Nano
, 13(5), 5833-5840.
Zamani Mahdi, Tütüncüoglu Gözde, Martí-Sánchez Sara, Francaviglia Luca, Güniat Lucas, Ghisalberti Lea, Potts Heidi, Friedl Martin, Markov Edoardo, Kim Wonjong, Leran Jean-Baptiste, Dubrovskii Vladimir G., Arbiol Jordi, Fontcuberta i Morral Anna (2018), Optimizing the yield of A-polar GaAs nanowires to achieve defect-free zinc blende structure and enhanced optical functionality, in Nanoscale
, 10(36), 17080-17091.
Semiconductor nanowires are filamentary crystals with a tailored diameter in the range from a few to about 100 nm. Thanks to their special morphology and reduced diameter, they hold great promise as building blocks for next generation applications in the electronic, optoelectronic, energy harvesting and storage domain. Research in semiconductor nanowires has made an extraordinary progress in the last decade. Many milestones have been achieved, and industry is progressively interested in these nanostructures. Semiconductor industry, including electronics and solar cell industry, builds devices mostly on (100) oriented substrates. However, nanowires grow mostly in the (111) direction. Recipes for nanowire growth in the (100) direction would significantly ease the integration of nanowires into existing technology platforms. They would for example enable the integration of III-V semiconductors on the CMOS platform. An additional advantage of growing nanowires in the (100) direction is that a growth front in this direction locks the formation of stacking defects (details in the proposal). As a consequence, defect-free single crystalline nanowires can be obtained. Today, III-V (100) oriented nanowires have mostly been obtained by the use of Au-assisted vapor-liquid-solid (VLS) method. Au preferentially gathers vapor precursors that decompose underneath in the form of a solid nanowire. Growth along the (100) direction has been achieved by the Samuelson and Bakkers groups by careful modification of the contact angle of the Au droplet with the substrate/nanowire. This has been obtained by adjusting the surface energies of both the substrate prior to growth and the Au droplet (for example by alloying it with lower energy elements or surfactants). Still, the use of Au in the fabrication of electronic or photonic semiconductor devices is incompatible with the current semiconductor industry. Nanowires obtained in a Au-free manner would offer a much larger technological impact. In our group, we grow III-V nanowires by the so-called self-assisted method where one intentionally avoids the use of Au. For example, for VLS growth of GaAs nanowires along (111) direction, Au droplets have successfully been replaced by Ga droplets. In this project, we propose to go beyond these earlier studies and engineer the self-assisted growth of III-As nanowires in the (100) direction to obtain a high yield of defect-free nanowires. Defect-free nanowires are key for e.g. high-efficiency solar cells and nanowire-based quantum information devices where electron scattering at crystal defects needs to be avoided. To gain technological relevance, large amounts of defect-free nanowires, as proposed here, will be required. In our research plan, we will explore the two materials GaAs and InAs that provide us with different band gaps, effective electron masses, Schottky Barrier heights and spin-related properties (Landé factor, spin-orbit coupling strength). In bulk form, these materials are known for instance for their excellent optoelectronic and high-frequency characteristics, respectively. We intend to answer to following fundamental questions:?What are the underlying mechanisms determining the growth direction of III-As nanowires??What is the effect of the initial contact angle of the Ga droplet in the growth direction of GaAs nanowires on (100) substrates??Is it possible to influence the growth direction of InAs nanowires by using an In droplet at the initial stage of growth??Do the initial conditions for nucleating a (100)-oriented nanowire change for steady-state growth??Does the contact angle of the VLS droplet have an impact on the shape of the liquid-solid interface? If yes, how does this affect the preferred growth direction? ?What growth directions are physically limited due to surface energy considerations??Is it possible to grow (100)-oriented III-V nanowires in an ordered fashion by pre-patterning a substrate and in a self-assisted fashion??Do (100) oriented III-As nanowires provide new possibilities for quantum heterostructures?