An effective tunnelling recombination junction (TRJ) is the most important part in a series connected tandem solar cell, and it always plays a significant role to match the current densities of individual solar cells. The aim of this paper is to find a TRJ that shows more efficient ohmic behavior compared to that used in typical thin film tandem solar cells, due to high current nature. Silicon heterojunction (SHJ) based tandem solar cell structure (a-Si:H/SHJ) was studied in detail with simulations using Advanced Semiconductor Analysis (ASA) software. Trap assisted recombination tunnelling and field enhanced mobility mechanisms have been included in our model analysis. Moreover, we also have simulated individual device characteristics of each a-Si:H (n-i-p), SHJ cell (top and bottom subcells of an a-Si:H/SHJ tandem cell), and correlated with the performance of the a-Si:H/SHJ tandem solar cell. The tandem device with a TRJ, the type which used in a thin film silicon tandem cell, shows low open circuit voltage (Voc) = 1.12 V and poor fill factor (FF) = 0.29 with S-shape in light current density-voltage (J-V) characteristics due to charge transport issue at the interface of top and bottom cells. An appropriate TRJ gives efficient recombination and an excellent ohmic contact at the interface between the subcells to match the current of each device. With the implementation of the optimum TRJ at the junction of two cells, Voc and FF have improved significantly to 1.35 V and 0.79 respectively. Also, we observed that the Voc of the tandem solar cell is nearly equal to the sum of the corresponding individual subcells, confirming no trapping related field loss at the junction. © 2019 Elsevier Ltd. All rights reserved.