Question

Role of oxygen in the work function modification at various stages of chemically synthesized graphene

Answer 1

Correlation between the work function and oxygen content at various stages during synthesis of graphene by chemical route is presented. The values of work function in terms of contact surface potential difference (CPD) were estimated using a scanning Kelvin probe method. Oxygen content was determined using energy dispersive X-ray absorption (EDAX), and the data was further supported using the Rutherford back scattering method in oxygen resonance mode. Results indicated a linear correlation between the oxygen content and measured values of CPD at various stages during the chemical synthesis of graphene.

... The observed duality in the HOPG/ZnO junction type (Schottky type/ohmic) is attributed to the adsorption of oxygen atoms to the HOPG surface at the junction, which heightens the work function of the HOPG substrate and alters the energy diagram of the device as shown in Fig. 3b.The oxygen adsorption-caused work function increase is a well-known phenomenon in metals [14, 19]. In graphene-based materials, the predicted work function rise due to 17% surface coverage with oxygen atoms is 0.4 eV [20]. Fig. 3bdemonstrates the energy barrier build up at the junction in the presence of adsorbed oxygen atoms at ~28% surface coverage. ...

Role of Oxygen in the Work Function Modification at Various Stages of Chemically... | Request PDF. Available from: https://www.researchgate.net/publication/263618956_Role_of_Oxygen_in_the_Work_Function_Modification_at_Various_Stages_of_Chemically_Synthesized_Graphene [accessed Mar 03 2018].