Comparison of characteristics of α-PbO and β-PbO photoconductors for digital X-ray detectors

Abstract

There have been recent investigations on direct conversion materials and photoconductors, which generate electron–hole pairs (EHPs), for X-ray image acquisition. In this paper, we compare the characteristics of lead oxides of specific phases. We prepared litharge, the red tetragonal lead oxide α-PbO, from massicot, the yellow orthorhombic oxide β-PbO, and fabricated films by the particle in binder (PIB) method. Structural and optical characteristics of the fabricated lead oxide films were investigated using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Also, we measured electrical properties of the films and compared X-ray sensitivities, leakage currents and Signal to Noise Ratio (SNR) of tetragonal α-PbO and orthorhombic β-PbO. The electrical properties and X-ray sensitivities of tetragonal α-PbO films were similar to those of orthorhombic films, but the leakage current of α-PbO films was about 0.5 pA/mnf while the leakage current of the other films was about 3.5 pA/mnf. We therefore conclude that the electrical properties of tetragonal α-PbO films are better. In results reported here, however, we did not succeed in creating pure tetragonal α-PbO from orthorhombic β-PbO, indicating that more research is needed on the preparation of pure α-PbO material.