Imaging the electrostatic landscape of unstrained self-assemble GaAs quantum dots

Autor(es)

Lanzoni, Evandro Martin ^{[1, 2, 3]} ; da Silva, Saimon F. Covre ^{[2, 4, 5]} ; Knopper, Matthijn Floris ^[6] ; Garcia, Ailton J. ^{[7, 2, 5]} ; Rodrigues Costa, Carlos Alberto ^[2] ; Deneke, Christoph ^[7]

Afiliação do(s) autor(es)

^[1] Sao Paulo State Univ Unesp, Inst Sci & Technol, BR-18087180 Sorocaba - Brazil

^[2] Brazilian Ctr Res Energy & Mat CNPEM, Brazilian Nanotechnol Natl Lab LNNano, BR-13083970 Campinas - Brazil

^[3] Univ Luxembourg, Phys & Mat Sci Res Unit, L-1511 Luxembourg - Luxembourg

^[4] Univ Fed Vicosa UFV, Dept Fis, BR-36570000 Vicosa, MG - Brazil

^[5] Johannes Kepler Univ Linz JKU, Inst Semicond & Solid State Phys, A-4040 Linz - Austria

^[6] Eindhoven Univ Technol TU E, Dept Appl Phys, NL-5600 Eindhoven - Netherlands

^[7] Univ Estadual Campinas, Inst Fis Gleb Wataghin, BR-13083859 Campinas - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Nanotechnology; v. 33, n. 16 APR 16 2022.
• Citações Web of Science: 0

Resumo

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 center dot 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 center dot 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. (AU)

• Processo FAPESP: 16/14001-7 - Crescimento e fabricação de estruturas de membranas semicondutores para a pesquisa básica e aplicações de dispositivos potenciais
• Beneficiário: Christoph Friedrich Deneke
• Modalidade de apoio: Auxílio à Pesquisa - Regular