Controlled Doping Engineering in 2D MoS₂ Crystals toward Performance Augmentation of Optoelectronic Devices

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Doping engineering of 2D semiconductors is crucial for device applications.
• Inhomogeneous doping distribution in ultrathin 2D materials limits performance.
• Controlling dopant distribution is essential for realizing the full potential of 2D materials.

Purpose of the Study:

• To achieve controlled doping of 2D molybdenum disulfide (MoS₂) with tin (Sn) heteroatoms.
• To improve the photodetection performance of MoS₂ flakes through substitutional doping.
• To investigate the impact of Sn doping on the MoS₂ lattice structure and electronic properties.

Main Methods:

• Single-step deposition method for Sn heteroatom doping into 2D MoS₂.
• Atomic-resolution and spectroscopic characterizations (e.g., TEM, XPS) to confirm doping.
• Photodetection performance measurements of pure and Sn-doped MoS₂ flakes.

Main Results:

• Successful substitutional doping of Sn atoms at Mo sites in the MoS₂ lattice without aggregation.
• Sn doping induces additional strain in the MoS₂ host lattice.
• Sn-doped MoS₂ shows an order of magnitude improvement in photodetection performance (R_λ ≈ 29 A/W, EQE ≈ 7.8 × 10³%, D* ≈ 10¹¹ Jones@470 nm).

Conclusions:

• Substitutional doping of Sn in MoS₂ enhances photodetection due to released electrons from Sn atoms.
• The developed doping process provides a method to tune the properties of 2D transition metal dichalcogenides (TMDs) on demand.
• This approach offers a pathway for creating high-performance photodetectors and other advanced 2D electronic devices.