Ultrathin-Gold-Resonators-Enabled Bolometers with High Linearity, Responsivity, and Repeatability

Area of Science:

• Materials Science
• Nanotechnology
• Mechanical Engineering

Background:

• Ultrathin metal films possess unique optical and electronic properties distinct from bulk metals.
• These films hold significant potential for advanced sensing applications.
• Integrating mechanical degrees of freedom into ultrathin films could enhance sensing capabilities but remains underexplored.

Purpose of the Study:

• To demonstrate ultrathin gold nanomechanical resonant sensors with high-frequency vibrations.
• To investigate the potential of these devices as nanoscale bolometers.
• To explore the frequency scaling laws and material properties of these nanomechanical sensors.

Main Methods:

• Fabrication of ultrathin gold nanomechanical resonant sensors.
• Characterization of sensor vibrations in the high frequency (HF) and very high frequency (VHF) bands.
• Evaluation of sensor performance as nanoscale bolometers under varying laser power.

Main Results:

• Demonstrated robust high-frequency (HF and VHF) vibrations in ultrathin gold nanomechanical sensors.
• Achieved nanoscale bolometer functionality with good linearity (nonlinearity factor of 0.0865) and high power-to-frequency responsivity (∼-11.47 ppm·µW⁻¹).
• Exhibited excellent repeatability across a wide laser power range (2.3 µW-0.48 mW) and elucidated frequency scaling laws.

Conclusions:

• Ultrathin gold nanomechanical resonant sensors can operate as effective nanoscale bolometers.
• The study determined the Young's modulus (75.6 GPa) and pretension (0.09-0.8 N·m⁻¹) of the ultrathin gold.
• This research enables future wafer-scale design and on-chip integration of ultrathin metal nanomechanical sensors.