Electrometry by optical charge conversion of deep defects in 4H-SiC

Area of Science:

• Quantum sensing
• Materials science
• Solid-state physics

Background:

• Optically active point defects in materials like diamond and silicon carbide (SiC) are promising for sensing magnetic fields, electric fields, strain, and temperature.
• Current sensing techniques primarily utilize the spin state relaxation and coherence times of these defects.

Purpose of the Study:

• To demonstrate that the charge state of point defects can be used for environmental sensing, specifically for high-frequency electric fields.
• To develop an all-optical high-frequency electrometer that complements existing spin-based sensing methods.

Main Methods:

• Utilizing optical charge conversion of point defects between photoluminescent and dark charge states.
• Measuring the conversion rate's dependence on the electric field (energy density).
• Testing the technique in 4H-SiC using ensembles of divacancies and silicon vacancies across a range of temperatures.

Main Results:

• The defect charge state was successfully used to sense high-frequency electric fields.
• The technique was validated in 4H-SiC from cryogenic to room temperature.
• A sensitivity of [Formula: see text] was achieved.
• Spatial 3D maps of surface acoustic wave modes were obtained due to the piezoelectric nature of SiC.

Conclusions:

• The charge state of optically active point defects offers a novel pathway for high-frequency electric field sensing.
• This all-optical method provides a valuable alternative and complement to spin-based sensing techniques.
• The technique's application in SiC demonstrates its versatility and potential for advanced material characterization, including mapping acoustic waves.