Firstly, a 5mM BPO solution in acetone was prepared. The wafer with hBN/G sample was vertically held by a clean tweezer and slowly dipped in the BPO solution maintaining for 2 s, then carefully moved out placing on a glass slide. After 5 minutes evaporation of acetone under ambient condition, a uniform thin film of BPO was coated on the top of the whole hBN/G structure. Photochemical reaction was carried out by a 532 nm green Raman laser with spot size of 0.7 μm and 1 mW energy. The selective functionalization on hBN/G was realized by a point-by-point mapping function of the scanning Raman instrument with a square shape with steps of 0.7 μm ´ 0.7 μm. The irradiation time of every point was calculated accumulatively. For functionalization of hBN/G, we used 30 s acquisition time for every measured point. The laser illuminated only the bottom half part of the graphene flake with a rectangular map of 20 μm ´ 15 μm. After laser functionalization, the BPO molecule film was removed by acetone wash. The Raman spectra of the whole hBN/G structure were read out by the 532 nm laser with 1 s irradiation time and a lower energy of 0.5 mW, and other parameters remained the same.