High-performance current rectification in a molecular device with doped graphene electrodes

To achieve an excellent rectification for molecular rectifiers has been an unmet goal to date. Here, we report calculated results on high-performance molecular rectifiers, where two semi-infinite graphene electrodes are periodically doped with boron and nitrogen atoms, respectively. It is surprising to find that there exists a particular coupling selection for energy bands of electrodes to the central molecule and unique bias-polarity-dependent band matching relations between two electrodes, leading to an unexpectedly high rectification ratio (>109) in a large bias region. This is a much higher value than that for macroscopic p–n junction diodes (105–107), and typical behaviors for conventional diodes are also clearly observed. The robust rectifications are further tested by varying the length and type of molecules, doping concentrations, and width of electrodes.