Optical properties and photovoltaic effect in Pb2CrO5 thin films

Optical properties and the photovoltaic effect in Pb2CrO5 thin films, which are prepared by an electron-beam evaporation technique, are investigated. From the main peaks of the x-ray diffraction (XRD) patterns, which depend on the preparation condition, thin films are classified into three types: (1) (020), (2) (310), and (3) (200). The sample with a (310) main reflection has a similar XRD profile to that of the bulk material. A device to measure the photovoltiac response in the thin films has one pair of semitransparent Au electrodes on the same surface. All the Pb2CrO5 thin films had a photovoltaic response. The (310) sample shows the largest photosensitivity. In this sample the saturation photovoltage is 1.16 V at a light intensity of 23.25 mW/cm2. The absorption constant (α) of thin films in the visible region ranges between 4×103 and 1×105 cm−1. A band-gap energy of 2.3–2.4 eV is obtained from both plots of α2 and photovoltage as a function of photon energy.