Ana Sanchez.

Ana M Sanchez is currently a Professor in the Physics Department at Warwick University. Her research interests focus on correlating atomic structure with physical properties in nanomaterials, mainly in semiconductors and ferroelectric oxides. Throughout her career she has been collaborating with world-leading groups using advanced microscopy techniques both to determine defect structure in materials and the challenging and technologically relevant problem of determining strain and composition at nanometer scale. She have authored or co-authored more than 120 peer-reviewed articles in journals such as Nature Materials, Nature Nanotechnology, Nature Communications, Advanced Functional Materials, Physical Review B, Nano Letters, Applied Physics Letters, Crystal Growth and Design, Small, Soft Matter, etc.

Ana M Sanchez is currently a Professor in the Physics Department at Warwick University. Her research interests focus on correlating atomic structure with physical properties in nanomaterials, mainly in semiconductors and ferroelectric oxides. Throughout her career she has been collaborating with world-leading groups using advanced microscopy techniques both to determine defect structure in materials and the challenging and technologically relevant problem of determining strain and composition at nanometer scale. She have authored or co-authored more than 120 peer-reviewed articles in journals such as Nature Materials, Nature Nanotechnology, Nature Communications, Advanced Functional Materials, Physical Review B, Nano Letters, Applied Physics Letters, Crystal Growth and Design, Small, Soft Matter, etc.

Abstract.

Self-formed quantum wires and dots in core-shell nanowires for quantum photonics

 

  1. A. Fonseka1, A. V. Velichko2, Y. Zhang3, J. A. Gott1, G. D. Davis2, R. Beanland1, H. Liu3, D. J. Mowbray2 and A. M. Sanchez1

 

1 Department of Physics, University of Warwick, Coventry CV4 7AL, UK

2 Department of Physics and Astronomy, University of Sheffield, Sheffield, S3 7RH, UK

3 Department of Electronic and Electrical Engineering, University College London, London WC1E 7JE, UK

 Email: a.m.sanchez@warwick.ac.uk

Keywords: nanowire quantum wires, nanowire quantum dots, GaAsP nanowires

III-V semiconductor growth on Si substrates has the potential to reduce significantly device costs but also allows the direct integration of III-V light emitters with Si electronics. Growth on Si substrates will also reduce the dependence on scarce III-V materials. Nevertheless, there are significant challenges for the integration of III-V on Silicon due to the difference in lattice parameters and expansion coefficients. Nanowires offer an ideal solution, based on their small contact area with the substrate providing better tolerance to strain and effectively expelling dislocations. Additionally, self-assembly is a powerful strategy to generate quantum structures embedded within the nanowires, providing potential applications in photonic devices.

Fonseka el at.- Nano Letters 2019 19 (6), 4158-4165

Nanowire morphologies make growth on different facets possible, favoring the generation of unintentional self-formed structures. Although this process can deteriorate the device performance in some cases, it has been demonstrated that these unintentional structures exhibit superior optical properties to those grown intentionally. This talk will focus on the formation and characterization of quantum wires and quantum dots at the core-shell interface of twinned GaAsP-GaAsP nanowires. Details about location and distribution of these features will be elucidated based on the nanowire characteristics, such as polarity and composition.

Optical measurements by photoluminescence confirm the quantum emitter characteristics of the self-formed structures. Thus, the possibility to control the relative formation of QWRs or QDs, and resulting emission wavelengths of the QDs, by controlling the twinning of the nanowire core, opens new possibilities for designing nanowire devices.