On the dependence of photoluminescence lifetime on emission energy in porous silicon at various temperatures

Abstract Photoluminescence (PL) decay of porous silicon as a function of emission energies E PL is studied at temperatures 20–293 K to investigate why the PL lifetime decreases exponentially with increasing E PL at room temperature. We find that this exponential decrease gets less prominent with decreasing temperature and almost disappears below about 70 K. The PL lifetime at room temperature is thus implied to be affected greatly by thermally activated hopping of carriers, as qualitatively shown using luminescence dynamics on localized states in the porous cluster model.