A new type of heterojunction solar cell based on gallium phosphide/black silicon was considered. The nanostructured surface of black silicon (b-Si) was obtained by cryogenic etching in a SF6/O2 gas mixture. The average height of  the b-Si structures varies from 1.4 to 2.1 μm. The heterojunction was fabricated by low temperature method such as plasma-enhanced atomic-layer deposition (PEALD). According to transmission electron microscopy, the thicknesses of the deposited GaP layer are fixed to be 30 nm. The layer consists of crystallites aligned along the crystal lattice direction, as well as their twins. This thin GaP layer allowed achieving a fill factor of 54.5% without transparent  conductive oxide and with a test grid. The use of GaP layer as an emitter a broadening of the external quantum efficiency spectrum boundary in the short-wavelength region.