V_octransient in silicon heterojunction solar cells withµc-SiOx:H window layers

Abstract

Silicon heterojunction (SHJ) solar cells with hydrogenated microcrystalline silicon oxide (µc-SiOx:H) emitters are fabricated and studied using the open circuit voltage (V oc ) transient. The built-in electric field (E in ), minority carrier lifetime, hole mobility, and a-Si:H/c-Si heterointerface valance band offset (ΔE v ) of the solar cells can be excavated by the V oc transient. The rising rate of the V oc transient curve, which has not been studied in previous research, is found to be dependent on E in in SHJ cells. The measurements of the V oc transient curves at different excitation intensities are used as a powerful approach for analysis of the ΔE v difference between SHJ cells with different µc-SiOx:H emitters. Based on this analysis, it is demonstrated that the origin of the S-shaped J-V characteristics of SHJ cells lies in an inferior E in and/or severe interface ΔE v , and the role of ΔE v is more dominant.

Simulation of a-Si:H/c-Si heterojunction solar cells: From planar junction to local junction*

“…The reason may be that the property of alternative materials is not good enough and big band offset deteriorates cell performance. [12,16] Several groups [17][18][19][20][21] reported that the emitter of the a-Si:H layer can be placed at the back side of the cell for avoiding the absorption of the doped a-Si:H layer, i.e., interdigitated back contact (IBC) technology has been used for the silicon heterojunction solar cell. The solar cell with the combination of the HIT and IBC technologies has achieved a world-record efficiency of over 26%.…”