Solar cells with p-i-n structure, which can be found in the form of quantum well, quantum dot and nanotubes, have recently been in the center of scientific consideration because they can enhance efficiency of the cell. The main processes in a quantum well solar cell (QWSC) are recombination and traort. Resonant tunneling (RT) is the most important phenomenon in traort. The cells are consisted from two main parts: the leads in the sides and the central part that contain several atomic layers. In this research, using non-equilibrium green's function theory, we focused on the study of RT in such a system. To do this, we use a single band tight-binding model. The Hamiltonian is in terms of the kinetic energy, the band structure and band offset parts, and also the Hartree potential. Then using equation of motion in stationary state, the green's function can be obtained. At the first step we solve the Poisson's equation to calculate the potential at the layer L. The local density of states (LDOS), and current density versus bias voltage are driven, for a bulk sample. Then the same parameters for single and double quantum well samples are calculated. The results show, LDOS is localized in a quantum well, and current density in p-i-n system exhibits nonlinear behavior. Adding single quantum well in the intrinsic region, a resonance in 0.11 volt is achieved. Furthermore, in the symmetrical double quantum well, the first resonance occurs in 0.019 volt and the second this in 0.059 volt.
