Interface charge modulation in lead sulphide-ferroelectric ceramic heterostructures

• Published in: Infrared physics & technology 1996-10, Vol.37 (6), p.659-665
• Main Authors: Pintilie, I., Pintilie, L., Pentia, E., Botila, T., Ofrim, D.
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electrical properties of specific thin films; Electrical properties of specific thin films and layer structures (multilayers, superlattices, quantum wells, wires, and dots); Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport phenomena in thin films and low-dimensional structures; Exact sciences and technology; Photoconduction and photovoltaic effects; Photoconduction and photovoltaic effects; photodielectric effects; Physics
• ISSN: 1350-4495; 1879-0275
• DOI: 10.1016/S1350-4495(96)00004-7

An anomalous high signal was observed across lead sulphide-ferroelectric ceramic heterostructures illuminated at room temperature with light having wavelengths between 0.8 and 3.1 μm. The frequency characteristic of this signal is similar to a high-pass filter and depends on the value of the load resistance in series with the lead sulphide thin film. This signal is only two to three times smaller than the usual photoconductive signal generated by the lead sulphide thin film. Its nature is not pyroelectric because of its frequency dependence. The interface charge released from the PbS-ferroelectric interface during polarization reversal was integrated and a hysteresis loop was obtained. Electrons and hole concentrations were evaluated from this curve. The values obtained are: 4.4 × 10 16 cm −3 for holes and 3.4 × 10 16 cm −3 for electrons.