The improvement of the n(+)-doped-layer free a-Si:H thin film solar cell (TFSC) has been investigated in this work. The better ohmic contact characteristic has been achieved by adding the p.-Si:H layer between the a-Si:H and CuMg alloy. The proposed structure has showed the better solar cell characteristic than the previous n(+)-doped-layer free a-Si:H TFSC. An initial efficiency (eta) of 6.6% has been obtained with an open-circuit voltage (Voc) of 0.81 V, a short-circuit current density (Jsc) of 14.6 mA/cm(2) and a fill factor (F.F.) of 0.56. Furthermore, the band gap discontinuity of a-Si:H/mu-Si:H layer also improved the device performance. (c) 2012 Elsevier Ltd. All rights reserved.