IMPROVED OPTICAL-EMISSION OF POROUS SILICON WITH DIFFERENT POSTANODIZATION PROCESSES

Time integrated and time resolved photoluminescence measurements have been performed at room temperature on porous silicon samples prepared under identical conditions but processed after anodization in four dif ferent wats. New and simple treatments were made to reduce the structu ral damage due to the drying process. The results show that suitable c onditions exist to substantially improve the optical emission of porou s silicon samples. The observed modifications of the time integrated p hotoluminescence signal are related to dangling bonds produced during the drying process that are supposed to act as trap states in the elec tron-hole or excitons recombination mechanism. Time resolved measureme nts provide an evaluation of the relative density of trap states for e ach analyzed sample. (C) 1995 American Institute of Physics.