Abstract Trilayer thin films of Cu/Se/Al have physically deposited using vacuum thermal evaporation technique at pressure of 10 −5 Torr onto a glass substrate. Before and after annealing at different temperatures, various properties of these trilayer thin films, including the structure, optical absorption, optical band gap, current–voltage measurements and morphology have been studied and discussed. These properties have been characterized by X-ray diffraction (XRD), UV–vis spectrophotometer, 2 point probe and optical microscope at room temperature. Crystalline nature, resistance and band gap of annealed Cu/Se/Al trilayer thin films have been found to be increased comparative to the as deposited samples. Surface topography of as deposited and annealed trilayer thin films has been confirmed by 2D and 3D images of optical micrographs.