[Paper Review] Atomically sharp 1D SbSeI, SbSI and SbSBr with high stability and novel properties for microelectronic, optoelectronic, and thermoelectric applications

Bo Peng, Ke Xu+8 more|arXiv (Cornell University)|Mar 16, 2017

2D Materials and Applications3 citations

TL;DR

This study proposes three new atomically sharp 1D semiconductors—SbSeI, SbSI, and SbSBr—via first-principles calculations, demonstrating high dynamical and thermal stability. The 1D confinement induces a dramatic increase in band gap, effective mass, and Seebeck coefficient, enabling ultra-scaled transistors, strain-tunable optoelectronics, and enhanced thermoelectric performance, with experimental synthesis via exfoliation or hydrothermal methods shown to be feasible.

ABSTRACT

In scaling of transistor dimensions with low source-to-drain currents, 1D semiconductors with certain electronic properties are highly desired. We discover three new 1D materials, SbSeI, SbSI and SbSBr with high stability and novel electronic properties based on first principles calculations. Both dynamical and thermal stability of these 1D materials are examined. The bulk-to-1D transition results in dramatic changes in band gap, effective mass and static dielectric constant due to quantum confinement, making 1D SbSeI a highly promising channel material for transistors with gate length shorter than 1 nm. Under small uniaxial strain, these materials are transformed from indirect into direct band gap semiconductors, paving the way for optoelectronic devices and mechanical sensors. Moreover, the thermoelectric performance of these materials is significantly improved over their bulk counterparts. Finally, we demonstrate the experimental feasibility of synthesizing such atomically sharp V-VI-VII compounds. These highly desirable properties render SbSeI, SbSI and SbSBr promising 1D materials for applications in future microelectronics, optoelectronics, mechanical sensors, and thermoelectrics.

Motivation & Objective

• To identify stable, experimentally feasible 1D semiconductors with superior electronic and thermoelectric properties for next-generation nanodevices.
• To address the limitations of bulk V-VI-VII semiconductors, such as small band gap and high dielectric constant, which hinder their use in ultra-scaled field-effect transistors.
• To explore the impact of dimensionality reduction (bulk to 1D) on electronic structure, including band gap, effective mass, and dielectric constant, via quantum confinement effects.
• To evaluate the potential of these 1D materials for optoelectronic and thermoelectric applications, particularly under mechanical strain and doping.
• To demonstrate the experimental feasibility of synthesizing these 1D materials through exfoliation, hydrothermal, or sonochemical methods.

Proposed method

• Employed density functional theory (DFT) with PBE-D2 functional to optimize the crystal structures of bulk and 1D SbSeI, SbSI, and SbSBr.
• Conducted phonon dispersion and density of states (DOS) calculations to confirm dynamical stability of the 1D phases.
• Performed molecular dynamics simulations at 300 K to verify thermal stability of the 1D SbSeI structure over 8 ps.
• Calculated electronic band structures, effective masses, and static dielectric constants to analyze quantum confinement effects in 1D systems.
• Applied uniaxial tensile strain (up to 3%) to investigate strain-induced band gap transitions from indirect to direct in 1D SbSeI.
• Used semiclassical Boltzmann transport theory to compute Seebeck coefficient and electronic figure of merit (zT) at 300 K for thermoelectric performance evaluation.

Experimental results

Research questions

• RQ1 Can 1D V-VI-VII compounds such as SbSeI, SbSI, and SbSBr be stabilized with atomically sharp morphology and high thermal and dynamical stability?
• RQ2 How does the bulk-to-1D transition affect key electronic properties like band gap, effective mass, and dielectric constant due to quantum confinement?
• RQ3 Can small uniaxial strain induce a transition from indirect to direct band gap in 1D SbSeI, enabling enhanced optoelectronic performance?
• RQ4 To what extent is the thermoelectric performance of these 1D materials improved compared to their bulk counterparts?
• RQ5 Is the experimental synthesis of these 1D materials feasible via exfoliation, hydrothermal, or sonochemical methods?

Key findings

• The 1D SbSeI phase exhibits high dynamical and thermal stability, confirmed by phonon dispersion and molecular dynamics simulations at 300 K.
• The 1D SbSeI shows a band gap increase from ~0.6 eV (bulk) to ~1.2 eV due to quantum confinement, making it a promising channel material for transistors with gate lengths below 1 nm.
• The effective mass in 1D SbSeI increases significantly due to quantum confinement, enhancing carrier localization and contributing to higher Seebeck coefficient.
• Under a 3% tensile strain, 1D SbSeI undergoes an indirect-to-direct band gap transition, enabling strong optical absorption and potential use in optoelectronic and mechanical sensing devices.
• The Seebeck coefficient of 1D SbSeI is substantially larger than in bulk SbSeI, and the electronic figure of merit (zT) reaches higher values over a wider doping range, indicating superior thermoelectric performance.
• The ideal cleavage energy of SbSeI (0.52 × 10⁻⁹ J/m) is much lower than that of graphite, indicating that mechanical exfoliation is experimentally feasible for isolating 1D chains.