Pyroelectric Effect Induced by the Builtin Field in the pn Junction of the Quantum Parael.pdf

Pyroelectric Effect Induced by the Built-in Field in the p-n Junction of the Quantum Paraelectric PbTe: Experimental Study A. V. Butenko, V. Sandomirsky, R. Kahatabi, and Y. Schlesinger Department of Physics, Bar-Ilan University, Ramat-Gan 52900, Israel Z. Dashevsky and V. Kasiyan Materials Engineering Department, Ben-Gurion University of the Negev, P.O.B. 653, Beer-Sheva 84105, Israel Abstract We report here the first observation of a pyroelectric effect in a non-polar semiconductor. This effect originates in the temperature dependent electric dipole of the p-n junction. The junction was illuminated by a chopped CO laser beam, and periodic 2 and single-pulse pyroelectric signals were observed and measured as a function of temperature, reverse bias voltage and chopper frequency. The measured pyroelectric -3 2 coefficient is 10 µC/cm K in the region of 40−80 K. The theoretical model describes quantitatively all experimental features. The time evolution of the temperature inside the junction region was reconstructed. The standard pyroelectric effect (PE) is usually observed only in crystals possessing polar axis symmetry [1]. However, in any non-polar solid, a built-in electric field, such as in the semiconductor barrier structures: p-n junctions (PNJ), Schottky contacts, heterojunctions etc. [2], creates a polar direction, or an electric dipole moment. If the dipole moment of the depleted area of a p-n junction varies with temperature, it can generate a pyroelectric effect, the junction barrier pyroelectricity, JBP. The magnitude of