The states of a single electron trapped in two laterally coupled quantum dots are studied theoretically in the framework of the effective mass and envelope function approximations. The electron tunneling between dots is studied by varying of inter-dot distance and we showed that the lateral quantum coupling between them allows the formation of molecular-like states, which exhibit similar characteristics to those of a molecule H 2 + . The effect of an in-plane electric field on the energy spectrum is analyzed and our results reveal that the wavelength of photons emitted from the system can be tuned by simply applying a low-intensity electric field. This latter feature is consistent with experimental observations.