Bi-doped CoTe nanoparticles for nonlinear and optoelectronic applications

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Cobalt Telluride (CoTe) nanoparticles possess exceptional properties valuable for optoelectronics.
• Doping nanomaterials with metal elements can enhance their characteristics and expand applications.

Purpose of the Study:

• To synthesize Bismuth (Bi)-doped CoTe nanoparticles via a straightforward hydrothermal method.
• To investigate the structural, optical, and photoresponse properties of Bi-doped CoTe nanoparticles.

Main Methods:

• Hydrothermal synthesis was employed to create four samples with varying Bi doping concentrations.
• Characterization techniques included X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), and X-ray photoelectron spectroscopy (XPS).
• Optical properties were analyzed using UV-Vis spectroscopy, and photoresponse was studied to determine photocurrent and nonlinear absorption coefficients.

Main Results:

• XRD confirmed the hexagonal CoTe phase with shifts due to Bi incorporation.
• TEM verified the CoTe phase and nanoparticle morphology, unaffected by Bi concentration.
• UV-Vis spectroscopy showed a reduced bandgap (3.35–1.64 eV) and an increased refractive index (2.00–3.08).
• Photoresponse studies yielded photocurrents from 229 to 810 μA, with a maximum nonlinear absorption coefficient (β) of 1.448 cm W⁻¹.

Conclusions:

• Bi-doped CoTe nanoparticles were successfully synthesized, retaining their hexagonal phase and nanoparticle structure.
• The doping effectively modified optical properties, including bandgap reduction and increased refractive index.
• The enhanced photoresponse and nonlinear absorption characteristics highlight the material's promise for nonlinear photonics and optoelectronic devices.