Enhancing optoelectronic properties of SiC-grown graphene by a surface layer of colloidal quantum dots

Makarovsky, Oleg; Turyanska, Lyudmila; Mori, N.; Greenaway, Mark; Eaves, Laurence; Patan�, Amalia; Fromhold, Mark; Lara-Avila, Samuel; Kubatkin, Sergey; Yakimova, Rositsa

Abstract

We report a simultaneous increase of carrier concentration, mobility and photoresponsivity when SiC-grown graphene is decorated with a surface layer of colloidal PbS quantum dots, which act as electron donors. The charge on the ionised dots is spatially correlated with defect charges on the SiC-graphene interface, thus enhancing both electron carrier density and mobility. This charge-correlation model is supported by Monte Carlo simulations of electron transport and used to explain the unexpected 3-fold increase of mobility with increasing electron density. The enhanced carrier concentration and mobility give rise to Shubnikov-de Haas oscillations in the magnetoresistance, which provide an estimate of the electron cyclotron mass in graphene at high densities and Fermi energies up to 1.2 × 1013 cm-2 and 400 meV, respectively.

Citation

Makarovsky, O., Turyanska, L., Mori, N., Greenaway, M., Eaves, L., Patanè, A., Fromhold, M., Lara-Avila, S., Kubatkin, S., & Yakimova, R. (in press). Enhancing optoelectronic properties of SiC-grown graphene by a surface layer of colloidal quantum dots. 2D Materials, 4(3), https://doi.org/10.1088/2053-1583/aa76bb

• Journal Article Type: Article
• Acceptance Date: Jun 2, 2017
• Online Publication Date: Jun 19, 2017
• Deposit Date: Jun 6, 2017
• Publicly Available Date: Jun 19, 2017
• Journal: 2D Materials
• Electronic ISSN: 2053-1583
• Publisher: IOP Publishing
• Peer Reviewed: Peer Reviewed
• Volume: 4
• Issue: 3
• DOI: https://doi.org/10.1088/2053-1583/aa76bb
• Keywords: SiC-graphene, Unipolar charge correlation, Colloidal quantum dots, Monte Carlo simulations
• Public URL: https://nottingham-repository.worktribe.com/output/866859
• Publisher URL: http://iopscience.iop.org/article/10.1088/2053-1583/aa76bb/meta
• Contract Date: Jun 6, 2017