Growth of CuIn3Se5 layer on the CuInSe2 film and its effect on the photovoltaic properties of In2 Se3/CuInSe2 solar cells

The growth of CuIn₃Se₅ layer on CuInSe₂ films has been studied for the fabrication of CuInSe₂ solar cell, using the three-stage process. After growing the CuInSe₂ film, the film surface was quickly converted to a possible ordered vacancy compound (CuIn₃Se₅). AES depth analysis indicated the presence of a CuIn₃Se₅ layer on the CuInSe₂ surface. The energy bandgap shifted from 1.04 to 1.24 eV by the formation of CuIn ₃Se₅ phase on CuInSe₂ surface. Because the lattice parameters of CuIn₃Se₅ are smaller, the XRD peaks were shifted to higher 2θ values. In₂Se ₃/CuInSe₂ cells with a thin CuIn₃Se₅ layer at the interface yielded solar efficiency of 8.46% with an active area of 0.2 cm². The device fabricated from the films with a thick CuIn₃Se₅ layer on CuInSe₂ film displayed a double diode effect which was possibly caused the increase of junction interface