1 Room - Temperature H 2 Gas Sensing Characterization 2 of Graphene - doped Porous Silicon via a Facile 3 Solution Dropping Method 4 5

In this study, a graphene-doped porous silicon (G-doped/p-Si) substrate for low ppm H2 17 gas detection by an inexpensive synthesis route was proposed as a potential noble graphene-based 18 gas sensor material and to understand the sensing mechanism. The G-doped/p-Si gas sensor was 19 synthesized by a simple capillary force-assisted solution dropping method on p-Si substrates, 20 whose porosity was generated through an electrochemical etching process. G-doped/p-Si was 21 fabricated with various graphene concentrations and exploited as a H2 sensor operated at room 22 temperature. The sensing mechanism of the sensor with/without graphene decoration on p-Si was 23 proposed to elucidate the synergetic gas sensing effect generated from the interface between the 24 graphene and p-type silicon. 25 26