Question

Explain the contact potential. Use this to further explain why one expects to see pulses from a silicon diode detectors even when the bias voltage is not applied.

Answer 1

The contact potential, Δφ (measured in unit of energy, eV), is one of the most important parameters for understanding tip-induced band bending and tunneling spectroscopy. It is defined as the work function of the metallic tip, φm, minus that of the semiconducting sample, φs, where for the sample its work function is given by the electron affinity, χ, plus the difference in energy between the conduction band maximum and the Fermi-level, EC-EF. For the contact potential used throughout the SEMITIP program,

The contact potential, Δφ (measured in unit of energy, eV), is one of the most important parameters for understanding tip-induced band bending and tunneling spectroscopy. It is defined as the work function of the metallic tip, φm, minus that of the semiconducting sample, φs, where for the sample its work function is given by the electron affinity, χ, plus the difference in energy between the conduction band maximum and the Fermi-level, EC-EF. For the contact potential used throughout the SEMITIP program,

Most silicon particle detectors work, inprinciple, by doping narrow (usually around 100 micrometers wide) strips of silicon to turn them into diodes, which are then reverse biased. As charged particles pass through these strips, they cause small ionization currents that can be detected and measured.