Unintentional bubbles are formed when manufacturing devices using two-dimensional materials. Usually, these bubbles affect device performance degradation, but in the case of memory devices, an additional charge trap can be expected. We investigate the direct surface potential of bubbles formed in a hexagonal boron nitride (hBN)/multilayer graphene (MLG) heterostructure. Specifically, we study the electron transfer improvement by increasing the memory window of a MoS 2 /hBN/MLG heterostructure in floating gate memory owing to bubbles formed at the hBN/MLG heterointerface. This characterization of bubbles containing molecules such as water or hydrocarbon in two-dimensional material heterointerfaces can promote the understanding of charge carrier tunneling in two-dimensional material heterostructures.