Method and apparatus for measuring electrical properties of sample material, device and medium

A method for measuring electrical properties of a sample material performed by a microscope, comprising:

• applying an alternating voltage to a piezoelectric ceramic so that a probe fixed on the piezoelectric ceramic has vibration above a surface of the sample material, wherein the piezoelectric ceramic in the microscope has a length between 1 mm and 8 mm, a width between 1 mm and 4 mm, and a thickness between 1 mm and 3 mm, and wherein a radius of a tip of the probe is between tens of nanometers and several micrometers, the probe is a probe coated with a metal thin film, a probe coated with conductive diamond, or an all-metal probe;
• measuring a target contact potential difference between the probe and the sample material, and determining a target amplitude of an induced alternating current generated due to the vibration of the probe above the surface of the sample material;
• and
• determining a target work function of the surface of the sample material according to the target contact potential difference and a determined work function of the probe, and determining a target charge density of the surface of the sample material according to the target amplitude, the target contact potential difference, and a pre-stored target amplitude determination function for the induced alternating current,
• wherein the determining a target charge density of the surface of the sample material according to the target amplitude, the target contact potential difference, and a pre-stored target amplitude determination function for the induced alternating current comprises:
• determining the target charge density σ of the surface of the sample material according to the pre-stored target amplitude determination function for the target induced alternating current:
• A
• charge
• ω
• =
• (
• 1
• 1
• -
• (
• A
• 0
• d
• ε
• +
• h
• )
• 2
• -
• 1
• )
• ⁢
• 2
• ⁢
• (
• σ
• ⁢
• d
• ε
• +
• ε
• 0
• ⁢
• V
• C
• ⁢
• P
• ⁢
• D
• )
• ⁢
• S
• ⁢
• ω
• A
• 0
• ,
• the target amplitude
• A
• c
• ⁢
• h
• ⁢
• a
• ⁢
• r
• ⁢
• g
• ⁢
• e
• ω
• ,
• and the
• target contact potential difference VCPD, wherein h is a predetermined surface topography of the sample material and a preset height between the probe and the sample material, ω is a determined resonant frequency of the probe, A0 is a determined amplitude of the probe, d is a determined thickness of a dielectric, ε0 is a determined vacuum dielectric constant, ε is a determined relative dielectric constant, and S is an equivalent area of a tip of the probe.