One-source PVD of n-CuIn5Se8 photoabsorber films for hybrid solar cells

Abstract

Highly photosensitive CuIn5Se8 photoabsorber layers of n-type were deposited onto glass/ITO substrates from the bulk CuIn5Se8 source polycrystal by using the one-source physical vapour deposition (PVD) technique with following thermal annealing. The parameters of deposition process and thermal annealing were selected with the purpose to prepare photoabsorber layers for the hybrid photovoltaic structures based on inorganic and conductive polymer functional layers. As-deposited structures were annealed at the temperature range from 450 to 500°C in vacuum. Also, thermal annealing in argon and in vacuum in sequence was applied for the part of obtained structures according to conception of the sequential annealing. Obtained results show the chalcopyrite structure of prepared photoabsorber films and dominating presence of the CuIn5Se8 phase in the layers annealed in vacuum. It was found, that the CuIn5Se8 layers deposited at the temperature of substrate of 200°C and annealed at 500°C for 2h in vacuum show maximal photosensitivity under white light illumination with an intensity of 100mW/cm2. On the basis of the electrochemical impedance spectroscopy the order of charge carriers concentration in prepared photoabsorber layers was evaluated and n-type of conductivity confirmed.