Negative and positive electroluminescence from a compensated p-type germanium in terahertz frequencies

Abstract

Negative luminescence (NL) and positive luminescence in terahertz frequencies were observed from a compensated p-type Ge under various levels of pulse excitations at cryogenic temperatures. The NL spectra accompanying an S-type negative differential resistance phenomenon were attributed to the reduced emission transitions from the excited states to the ground states of the acceptors during the excitation. A possible excitation mechanism is also presented according to the measured data. (C) 2007 American Institute of Physics.