Artículos de revistas
Imaging the electrostatic landscape of unstrained self-assemble GaAs quantum dots
Date
2022-04-16Registration in:
Nanotechnology, v. 33, n. 16, 2022.
1361-6528
0957-4484
10.1088/1361-6528/ac47ce
2-s2.0-85123878559
Author
Universidade Estadual Paulista (UNESP)
Brazilian Center for Research in Energy and Materials (CNPEM)
Physics and Materials Science Research Unit
Universidade Federal de Viçosa (UFV)
Eindhoven University of Technology (TU/e)
Universidade Estadual de Campinas (UNICAMP)
Institutions
Abstract
Unstrained GaAs quantum dots are promising candidates for quantum information devices due to their optical properties, but their electronic properties have remained relatively unexplored until now. In this work, we systematically investigate the electronic structure and natural charging of GaAs quantum dots at room temperature using Kelvin probe force microscopy (KPFM). We observe a clear electrical signal from these structures demonstrating a lower surface potential in the middle of the dot. We ascribe this to charge accumulation and confinement inside these structures. Our systematical investigation reveals that the change in surface potential is larger for a nominal dot filling of 2 nm and then starts to decrease for thicker GaAs layers. Using k • p calculation, we show that the confinement comes from the band bending due to the surface Fermi level pinning. We find a correlation between the calculated charge density and the KPFM signal indicating that k • p calculations could be used to estimate the KPFM signal for a given structure. Our results suggest that these self-assembled structures could be used to study physical phenomena connected to charged quantum dots like Coulomb blockade or Kondo effect.