Published online by Cambridge University Press: 10 February 2011
The electric field dependence of emission of carriers from deep impurities in semiconductors has been investigated applying static and terahertz electric fields. It is shown that at high electric field strengths carrier emission is dominated by phonon assisted tunneling which may easily be recognized by plotting the emission rate as a function of the square of the electric field strength in a log-lin plot giving a straight line. For charged impurities the transition from phonon assisted tunneling to Poole-Frenkel effect at low fields can be traced back.