Origin of carbon and its influence on photoluminescence in porous silicon

Samples of porous Si (PS) were prepared from p-type 10–35 Ω-cm Si under anodisation in aqueous HF (20%) for 10 min. The composition of the PS was measured by heavy-ion elastic recoil detection analysis (HIERDA). In all samples a considerable carbon content varying from 2–20% was measured, while the oxygen and hydrogen concentrations ranged from 2–25% and 10–25%, respectively. The sample wax removing procedure was identified as a source for the high carbon content. The concentration of carbon and its influence on the photoluminescence due to different treatments of PS was investigated.