Single‐Side Heterojunction Solar Cell with Microcrystalline Silicon Oxide Emitter and Diffused Back Surface Field

The goal of high efficiency in Si solar cells has been developed to a close limit by Si heterojunction (SHJ) scheme. The further work should aim to simplify its fabrication process for the reduction of cost. In this study, a scheme single‐side heterojunction solar cell with hydrogenated microcrystalline silicon oxide emitter ((µc‐SiO_x:H(p⁺)) and diffused back surface field (BSF) was presented, to save the flip of wafers and the number of vacuum chambers. The device performance evolution was performed by AFORS‐HET simulation and experiments. It is demonstrated that FF of the solar cell is improved using diffused BSF to replace the intrinsic and doped stack hydrogenated amorphous silicon (a‐Si:H(n⁺/i)) layer in HIT solar cell, but J_sc and V_oc decreased. The former ascribes to the better conductivity of diffused BSF and band offset free in homojunction, the later the free carrier absorption in diffused region and the removal of rear a‐Si:H passivation layer. Further, the introduction of µc‐SiO_x:H(p⁺) emitter can compensate for the loss of J_sc above and increase FF, again, due to its wide band gap and high electrical conductivity, leading to a device performance similar to routine HIT device. This work provides a candidate for the roadmap of SHJ solar cells.