At the nanoscale, light interacts with matter in novel ways. There are many ways to affect the way light and matter interacts by designing suitable nanostructures. We investigate both how to understand the nanostructures on a quantum level as well as how to control light using nanostructures. Is it possible to improve optical devices using nanostructures? Can we go down and see exactly how nanostructures look?
Designed electron-photon interaction in nanostructures
Electrons in nanostructures are in quantum states and interact very differently with photons, compared with electrons in larger structures. It is for instance possible to design single-photon sources using nanostructures which is virtually impossible in large devices. In these small structures the dipole interaction does not apply very well. We study how we can use them to enhance device properties as well as to understand the electron-photon interaction.
Heterostructure physics with 3D control.
It has recently become possible to design nanostructures with atomically flat interfaces over large areas and it is also possible to design nanowires with diameters down to less than ten nanometers. The nanowires can also be overgrown which allows the fabrication of quantum dots, laterally confined quantum wells and quantum rings. We investigate the properties of these quantized structures using both optical and electrical means with an eye towards future devices as well as completely new phenomena such as novel phases of the electron gas. The figure illustrates different possibilities, and the different colours signify different materials or atoms.
Nanowire devices may have certain advantages for optical detectors. We investigate such devices in order to see how well they function as detectors. This is a complex area with many aspects to investigate, such as surface recombination, photon incoupling, current extraction and so on. The investigations covers devices operating from infrared to visible.
Confinement in thickness-controlled GaAs polytype nanodots N. Vainorius, S. Lehmann, D. Jacobsson, L. Samuelson, K. A. Dick, and M.-E. Pistol. . Nano letters 15, 2652-2656 (2015). DOI: 10.1021/acs.nanolett.5b00253
See article confinement in thickness-controlled nanodots at publisher's site
Wurtzite GaAs quantum wires: one-dimensional subband formation N. Vainorius, S. Lehmann, A. Gustafsson, L. Samuelson, K. A. Dick, and M.-E. Pistol. . Nano letters 16, 2774-2780 (2016). DOI: 10.1021/acs.nanolett.6b00482
See article wurtzite GaAs quantum wires at publisher's site
Radial band bending at wurtzite–zinc-blende–GaAs interfaces I. Geijselaers, S. Lehmann, K. A. Dick, and M.-E. Pistol. Nano Futures 2035002 (2018). DOI: 10.1088/2399-1984/aac96c
See article radial band bending at publisher's site
Crystal phase-dependent nanophotonic resonances in InAs nanowire arrays N. Anttu, S. Lehmann, K. Storm, K. A. Dick, L. Samuelson, P. M. Wu, and M.-E. Pistol. . Nano letters 14 5650-5655 (2014). DOI: 10.1021/nl502306x
See article crystal resonances at publisher's site
Mohammad Karimi, Infrared Photodetectors based on Nanowire Arrays with Embedded Quantum Heterostructures, PhD thesis, Lund University, 2020
See Mohammad Karimi's thesis at the Research Portal
Xianshao Zou, Dynamics of Photogenerated Charge Carriers in III-V Bulk and Nanowire Semiconductors PhD thesis, Lund University, 2020
See Xianshao Zou's thesis at the Research Portal
Neimantas Vainorius, Optical Studies of Polytypism in GaAs Nanowires PhD thesis, Lund University, 2017
See Neimantas Vainorius' thesis at the Research Portal
Yang Chen, III-V Nanowire Array Solar Cells: Optical and Electrical Modelling PhD thesis, Lund University, 2018
See Yang Chen's thesis at the Research Portal