The paper reports on the simulation studies of silicon based point contact back heterojunction solar cells using Silvaco Atlas tools. We also make use of band alignment diagrams connecting the entire cross-section of the device, from the emitter to the back surface field, to appreciate the operation of the solar cell. The effect of bias conditions on the band diagram and solar cell performance is explored. The influence of doping in the a-Si:H layer on the performance parameters is also investigated. In performing our investigation, we consider an optimized solar cell that shows a high efficiency of 24.49%, with a V-oc of 0.76 V, J(sc) of 38.29 mA/cm(2), and FF of 84.2. Further improvements in efficiency can be potentially achievable by using texturization and front surface field. (C) 2014 Elsevier Ltd. All rights reserved.