Two dimensional semiconductors with possible high room temperature mobility (1403.3872v1)

Abstract: We calculated the longitudinal acoustic phonon limited electron mobility of 14 two dimensional semiconductors with composition of MX$_2$, where M (= Mo, W, Sn, Hf, Zr and Pt) is the transition metal, and X is S, Se and Te. We treated the scattering matrix by deformation potential approximation. We found that out of the 14 compounds, MoTe$_2$, HfSe$_2$ and HfTe$_2$, are promising regarding to the possible high mobility and finite band gap. The phonon limited mobility can be above 2500 cm$^2$V$^{-1}$s$^{-1}$ at room temperature.

• The paper identifies MoTe₂, HfSe₂, and HfTe₂ as promising high-mobility 2D semiconductors with phonon-limited mobilities exceeding 2500 cm²V⁻¹s⁻¹.
• The methodology employs density functional theory and the Takagi model via FPLO code to assess electron effective mass and phonon interactions.
• Comparative analysis reveals that tailored crystal structures in these compounds offer advantages over MoS₂, potentially overcoming silicon-based device limitations.

Analysis of Two Dimensional Semiconductors with Potential High Room Temperature Mobility

The present analysis centers on the assessment of two-dimensional (2D) semiconductor materials, specifically those with a MX$_2$ composition, considering their potential for achieving high electron mobility at room temperature. This paper meticulously evaluates 14 MX$_2$ compounds, where M represents a transition metal (Mo, W, Sn, Hf, Zr, Pt) and X stands for chalcogens (S, Se, Te).

Key Findings

The research identifies MoTe$_2$, HfSe$_2$, and HfTe$_2$ as promising candidates, with phonon-limited mobility surpassing 2500 cm$^2$V$^{-1}$s$^{-1}$ at room temperature. These findings are predicated on deformation potential approximation using density functional theory (DFT). Critical parameters such as electronic band structures, electron effective mass, and phonon interactions were analyzed to compute electron mobility and band gaps.

Methodological Insights

Calculations were realized using the full-potential local-orbital code FPLO with a set density of k-points in the Brillouin zone. The analysis underscores the phonon as a dominant electron scattering source which intrinsically limits mobility. The Takagi model guided the computation of deformation potential, relating to acoustic phonons, employing parameters like effective mass and electron–phonon coupling.

The paper's detailed methodology, including the usage of scalar relativistic approximation and considerations of crystal structure, provided a robust framework for estimating mobility limits.

Comparative Analysis

Comparison with prior studies accentuates that MoS$_2$—a widely acknowledged 2D semiconductor—exhibits relatively low phonon-limited mobility due to its heavier effective mass and electron–phonon interactions. However, the examined compounds feature varying crystal structures (MoS$_2$ and CdI$_2$ types), affecting their electronic properties and anisotropy.

Implications and Future Directions

The detection of MX$_2$ compounds with high predicted mobility suggests significant implications for future electronic and logical device applications, particularly in contexts where silicon-based technology presents limitations. These materials could potentially offer superior performance in nanoelectronic devices owing to their significant mobility and suitable bandgaps.

Future work should encompass a broader spectrum of scattering mechanisms beyond acoustic phonons to enhance the precision of mobility predictions. Additionally, experimental verifications of the theoretical predictions are necessary to substantiate their applicability in practical scenarios.

In conclusion, this paper provides a valuable proposition for advancing semiconductor technology through the identification of high-mobility 2D materials. The outcomes suggest promising pathways for the development of non-Si based electronic components which could energize both research and industrial applications in semiconductor technologies.