Wet Chemical Etching (WCE) of Silicon is an adaptable method to create either films of freestanding nanowires on a silicon substrate or to produce spongy porous silicon structures. Especially the first kind is a potential candidate for the creation of novel thin film solar cells. Some time ago we already concluded that a two-media model appropriately describes the photoluminescence (PL) on the as-prepared samples and the HF-dipped samples. Recently, several methods of surface treatment and passivation were performed on the WCE samples, such as HF dips, passivation by methoxy groups and measurements in dilute HF. Furthermore, some samples were entirely oxidized either in water vapour. Effects of these surface and volume structural changes on steady state PL and on PL decay will be discussed.