Fast Photoluminescence Decay in a-SiNx:H Films

Abstract

ABSTRACTWe have used a fast analog technique (100 ps resolution) to study photoluminescence (PL) decay in a-SiNx:H films in nanosecond (0.1–50 ns) range. Films prepared using RF glow discharge of NF3 and pure SiH4 were used for these measurements. The PL decays in the films were studied as a function of nitrogen content for 0≤x≤0.13. When the PL decay measured at 25 K is fitted with I (t) = ao +Σai exp (-t/Ti), where ao, ai and ti, are fitting parameters, we get three distinct lifetimes with t1 = 0.8 ± 0.2 ns, T2 = 3.5 ± 0.5 ns and T3 = 14.0 ± 3.0 ns. We find that these lifetimes do not change with nitrogen content but their relative contributions to the PL decay change with nitrogen content. We have also studied the effect of temperature and excitation energy on the PL decays at different emission energies. We suggest an excitonic origin to these three recombination processes.