Formation and characteristics of a semiconductor field emission cathode

Research on germanium field emission cathodes made by an electrical breakdown process and the observation of these cathodes using a scanning electron microscope has shown that a long life cold surface with a short pulse of laser energy. A pulse of photons having the proper energy density heats a shallow area to the melting point, following which the Ge solidifies in a conical shape. These conical protuberances are of micron size and the small radius, of curvature at the apex produces a field enhancement factor on the order of 100. Field emission current can be drawn upon application of a sufficiently high electric field ( V/cm).