THE BARRIER THERMAL EMF AT A P-N-JUNCTION

The results of an experimental study of the magnitude and sign of the barrier thermo-emf at a p-n junction subjected to various types of app lied temperature gradients are presented. The method of calculation is based on phenomenological equations for the current densities of elec trons and holes, the equations of continuity for electrons and holes, and the Poisson equation for the electric field distribution along the structure. In contrast with the barrier-layer photovoltage, the barri er thermo-emf can have not only a forward-bias direction, but also a r everse-bias direction, depending on the position of the temperature gr adients and the physical parameters of the p-n structure. Experimental data that confirm both the computed values acid the sign of the barri er thermo-emf are presented. (C) 1995 American Institute of Physics.