Fabrication, simulation and experimental characterization of EWT solar cells with Deep Grooved Base contact

In this paper, we present a new solar cell design conceived for low–medium concentrator photovoltaic applications. The proposed cell is based on the emitter-wrap-through concept featuring grooved p-doped hole base contacts. The cell is fabricated by realizing an array composed of holes of two alternating doping types obtained by means of a deep reactive ion etching technique. Measurements under 1-sun illumination confirm the advantages of the considered architectures in terms of short-circuit current density and photon collection properties with respect to conventional front- and back-contact solar cells. Three-dimensional numerical simulations, calibrated starting from the measured dark J–V characteristics, are exploited to investigate the performance under concentrated light (maximum efficiency 21.4% at 44 suns) and to understand, especially in the case of highly resistive substrates, the impact of the p-doped holes depth in terms of resistive losses.