Electroluminescence of Ge/SiGe p-MODFETs

In order to investigate impact ionization we have performed electrical DC measurements and electroluminescence (EL) spectroscopy on strained Ge on Si0.4Ge0.6 p-MODFETs. These measurements are discussed in comparison with energy band structure calculation and high electric field transport simulation. The energy band diagram is calculated using an original 30 band k·p Hamiltonian taking into account strain. The transport simulation based on a matrix resolution of the Boltzmann transport equation allows us to calculate impact ionization coefficients. The interpretation of EL results is based on hole energy subbands calculated in the confined Ge quantum well.