Gas sensing by graphene/silicon hetrostructure

Graphene, a two-dimensional material with a very high charge carrier concentration, is ideal for sensing chemical species based upon charge exchange. The sensitivity of graphene is shown to improve many folds by using graphene/semiconductor heterostructure. A new amperometric chemical sensing paradigm based upon transport across graphene/p-Si Schottky diode under reverse bias is demonstrated in this work. The reported very high sensitivity of graphene/p-Si heterostructure is in direct agreement with small change in Schottky barrier height due to molecular adsorption on graphene causing large change in reverse saturation current due to exponential dependence of later on the former.