Charged Impurity Limited Scattering and Mobility in p-type GaS, GaSe, InS and InSe

ORAL

Abstract

The valence bands of many monolayer and few-layer two-dimensional (2D) materials such as GaS, GaSe, InS, and InSe, have a “Mexican hat” dispersion in which the valence band edge is approximately a ring in the 2D Brillouin zone. This results in a singular density of states (DOS) at the band edge that diverges as 1/√E. The ionized impurity scattering rate depends on the DOS through both the integral over final states and the polarization function in the screened Coulomb potential. We calculated the static charge polarizability within the random phase approximation and evaluated the ionized impurity scattering rate and the mobility as a function of temperature and carrier concentration. The results are compared to those obtained from Thomas-Fermi screening and a parabolic dispersion. The underestimation of the ionized impurity scattering rate using Thomas Fermi screening is strongly temperature dependent ranging from 2 orders of magnitude at 5K to a factor of 4 at 300K. At 77K, for an ionized impurity density of 1011 cm-2, the hole mobility of GaS ranges from 20 cm2/Vs at a hole concentration of 1012 cm-2 to 200 cm2/Vs at 1013 cm-2.

*This work is supported by the NSF EFRI-1433395, FAME, one of 6 centers of STARnet, a SRC program, and XSEDE, NSF ACI-1548562; allocation ID TG-DMR130081.

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Presenters

  • Protik Das

    • University of California, Riverside
    • Electrical and Computer Engineering, University of California, Riverside

Authors

  • Protik Das

    • University of California, Riverside
    • Electrical and Computer Engineering, University of California, Riverside

  • Darshana Wickramaratne

    • Materials Department, University of California, Santa Barbara
    • Materials Department, University of California - Santa Barbara
    • Materials Department, University of California
    • Electrical and computer Science engineering, University of California Riverside
    • Materials Department, Univ of California - Santa Barbara

  • Bishwajit Debnath

    • Electrical and computer Engineering, Univ of California - Riverside
    • Electrical and Computer Engineering, University of California, Riverside
    • Department of Electrical and Computer Engineering, University of California, Riverside
    • Department of Electrical and Computer Engineering, Univ of California - Riverside
    • Electrical and Computer Engineering, University of California Riverside

  • Gen Yin

    • Electrical Engineering, University of California, Los Angeles
    • Electrical and Computer Engineering, University of California, Los Angeles

  • Yafis Barlas

    • Univ of California - Riverside
    • Physics and Astronomy, University of California, Riverside
    • Computer and Electrical Engineering, University of California at Riverside
    • Physics, University of California, Riverside
    • University of California, Riverside

  • Roger Lake

    • Electrical and computer Engineering, Univ of California - Riverside
    • Department of Electrical and Computer Engineering, University of California, Riverside
    • University of California, Riverside
    • Univ of California - Riverside
    • Electrical and Computer Engineering, University of California, Riverside
    • University of Califoria Riverside
    • University of California Riverside
    • Department of Electrical and Computer Engineering, Univ of California - Riverside
    • Electrical and Computer Engineering, University of California Riverside