Intrinsic Charge Carrier Mobility in Single-Layer Black Phosphorus.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Semiconductor Physics

Background:

• Phonon scattering significantly impacts charge carrier mobility in 2D semiconductors.
• Anisotropic materials like black phosphorus (BP) present unique scattering mechanisms.
• Understanding scattering is crucial for optimizing electronic properties.

Purpose of the Study:

• To develop a theory for single- and two-phonon scattering in anisotropic 2D semiconductors.
• To apply this theory to single-layer black phosphorus (BP).
• To investigate the carrier concentration and temperature dependence of scattering and mobility.

Main Methods:

• Theoretical modeling of phonon-carrier interactions.
• Analysis of single- and two-phonon scattering processes.
• Calculation of carrier mobility in BP.

Main Results:

• Two-phonon scattering in BP is negligible at carrier concentrations above 10^13 cm^-2, unlike in graphene.
• Phonons exhibit anharmonic behavior at lower carrier densities.
• Electron mobility in BP shows significant anisotropy (μxx/μyy∼6.2), while hole mobility is less anisotropic (μxx/μyy∼1.4).
• Upper limits for mobility at room temperature are ~250 cm^2 V^-1 s^-1 for holes and ~700 cm^2 V^-1 s^-1 for electrons.

Conclusions:

• The developed theory provides insights into charge transport in BP.
• Anisotropy in electron mobility is a key characteristic of BP.
• The findings are essential for designing future electronic devices based on BP.