Graphene–semiconductor heterojunction sheds light on emerging photovoltaics

Electronic coupling of graphene atop a bulk semiconductor and the resultant interfacial energy-band reorganization create a light-sensitive junction only one atom below the front surface. Uniquely, this architecture leads to the surface being in extremely close proximity to the depletion region (typically buried several micrometres under the surface for a conventional wafer-based p–n junction solar cell), thus providing direct access to the photosensitive junction, which can be modified by surface functionalization and/or incorporation of plasmonic nanoparticles. The surface-based heterojunction, tunable carrier transport and relatively enhanced optical absorption in such 2D-layer-interfaced 3D semiconductor systems will have a transformative impact in the field of 2D optoelectronics, photovoltaics, photonics and nanoelectronics. Graphene-on-bulk semiconductors may enable new directions for ultrathin optoelectronics and photovoltaics.