Fabrication of MoOx/c-Si/MgOx carrier selective heterojunction solar cell.

In recent years, the photovoltaic community has been paying much interest to solar cells with dopant-free carrier selective contacts. In such solar cells, the collection of carriers is achieved by introducing a band offset due to the asymmetry in band alignment with silicon. These dopant-free carrier selective contacts can be deposited on c-Si through simple, low-temperature techniques such as evaporation, spin coating, spray pyrolysis, etc. This work demonstrates the carrier selective potential of MoO_x and MgO_x films by fabricating Au/MoO_x/n-Si/Ag and Al/MgO_x/p-Si/Au heterojunction diodes, respectively. Both heterojunction structures showed good diode behavior in the dark. Then we fabricated a double heterojunction carrier selective solar cell with MoO_x (where x is slightly less than 3) as the hole-selective layer (HSL) and MgO_x/Al stack (where x is slightly less than 1) as the electron-selective layer (ESL) on the front and rear side of a planar n-type c-silicon substrate. The thermal evaporation technique was chosen for the deposition of MoO_x and MgO_x, as a low-cost fabrication method for the crystalline silicon solar cell. ITO was used as the transparent front contact, over which the Ag grid was deposited. The performance of the fabricated Ag/ITO/MoO_x/n-Si/MgO_x/Al double heterojunction solar cell was analyzed. A power conversion efficiency of 3.73 % was obtained with a short-circuit current density of 20 mA/cm² and an open-circuit voltage of 410 mV. [ABSTRACT FROM AUTHOR]