  Strain in two-dimensional (2D) materials has attracted particular attention
owing to the remarkable modification of electronic and optical properties.
However, emergent electromechanical phenomena and hidden mechanisms, such as
strain-superlattice-induced topological states or flexoelectricity under strain
gradient, remain under debate. Here, using scanning photocurrent microscopy, we
observe significant photocurrent enhancement in hybrid vertical junction
devices made of strained few-layer graphene and InGaN quantum dots.
Optoelectronic response and photoluminescence measurements demonstrate a
possible mechanism closely tied to the flexoelectric effect in few-layer
graphene, where the strain can induce a lateral built-in electric field and
assist the separation of electron-hole pairs. Photocurrent mapping reveals an
unprecedentedly ordered hexagonal network, suggesting the potential to create a
superlattice by strain engineering. Our work provides insights into
optoelectronic phenomena in the presence of strain and paves the way for
practical applications associated with strained 2D materials.
