Structural changes during vapor-phase deposition of polycrystalline-PbI2 films

Lead iodide (PbI2) polycrystalline thin films with [0 0 1] and [1 1 0] orientations have been grown using a physical vapor-deposition method on substrates coated with ITO or gold electrodes. The films orientation as function of the deposition conditions, such as substrate temperature and coating material, was characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Four different types of structures of PbI2 films deposited on ITO were identified and named A, B, C and D, where each structure is stable in its own temperature range. Changes of structure during the growth process due to the temperature range change were demonstrated. Moreover, the dependence of the temperature range and film structure on substrate coating materials was found. The electrical properties and detector response correlation with film structure have been summarized.