Nitrogen oxide gas sensor based on sulfur doped graphene and preparation method therefor

A nitrogen oxide gas sensor based on sulfur doped graphene and a preparation method therefor. The method comprises the following steps: 1) providing graphene (21) and a micro-hotplate substrate (23), and transferring the graphene (21) onto the micro-hotplate substrate (23); 2) putting the micro-hotplate substrate (23) with its surface covered by the graphene (21) into a chemical vapor deposition reactor; 3) performing gas injection and gas exhausting treatment on the reactor by using inert gas; 4) synchronously injecting both the inert gas and hydrogen into the reactor at a first temperature; 5) injecting the inert gas, hydrogen, and sulfur source gas into the reactor at a second temperature for reaction, so as to implement sulfur doping of the graphene (21); 6) stopping injecting the sulfur source gas, and decreasing the temperature in the protective atmosphere of hydrogen and the inert gas. The preparation method can use a wafer-scale substrate, implement wafer-scale preparation, reach a batch manufacturing level, and greatly decrease the production costs. The prepared gas sensor has high sensitivity and selectivity for nitrogen oxide gas molecules.