Room temperature electroluminescence from a c-Si p-i-n structure

The time dependent electroluminescence (EL) of c-Si (at 1.1 eV) is investigated at room temperature for a p-i-n structure under excitation with forward biased current pulses. The EL intensity increases by square law at shorter times (<3 μs) and reaches a steady state value at longer times (>10 μs). The parabolic dependence of the EL intensity on the current density at the shorter times points to the bimolecular recombination mechanism. The EL response time has been decreased to less than 200 ns for the given p-i-n structure by application of a reverse bias potential. The maximal EL quantum efficiency is of the order of 0.01% for the investigated p-i-n structure and possible ways to increase this value are discussed.