1.Mott-Schottky curve method
CS series electrochemical workstation can be used for semiconductor or passivation film Mott-Schottky diagram testing. By superimposing an AC disturbance signal with a fixed amplitude and a fixed frequency under different DC potentials, the impedance values under different DC potentials are measured, and the depletion region capacitance Csc is calculated according to the imaginary part of the impedance, . Finally, the Mott-Schottky figure is calculated and drawn according to the formula (or 2 ), and calculate the carrier concentration in the semiconductor or passivation film material accordingly to determine the semiconductor characteristics of the material.
formula , V fb is flat band potential (flat band potential), N d and N a are donor (donor) and acceptor (accepter) carrier concentration respectively, ε is the relative dielectric constant , ε0 is the vacuum dielectric constant , A is the electrode surface area , k is the Boltaman constant , T is the absolute temperature , and e is the charge quantity.
C SC can be calculated according to the formula (3 )
, where Z "is the imaginary part of impedance and f is the sine wave frequency.
impedance - potential scan introduction
connect the electrolytic cell device to CS350 electrochemical workstation, and select "P impedance - potential scan " test method from corrTest software, and set parameters as shown in figure 1 ( is for reference only )