Current–voltage and low-frequency noise characteristics of structures with porous silicon layers exposed to different gases

Current–voltage and noise characteristics of porous silicon (PS)/single crystalline silicon (SCS) samples were measured under exposure to dry air, air +0.4% CO, dry air +1.7% CO, and dry air+ethyl alcohol vapor. The samples have a sandwich structure comprising Al/PS/SCS/Al. For the dry air +CO mixtures, the noise level was sensitive not only to the presence of CO but also to its percentage, and an increase of the CO concentration led to a change in the spectral density function of the low-frequency noise.