A full-coupling model of PN junctions based on the global-domain carrier motions with inclusion of the two metal/semiconductor contacts at endpoints

A full-coupling model on the current-voltage (J-V) characteristics of PN junctions is put forward in the paper by taking into account both the whole junction and the two electrode regions consisting of metal/semiconductor (M/S) contacts. The depletion layer assumption proposed by the Shockley model is discarded. Gauss’ law on the electric potential and the electric field is applied in the whole junction region such that the majority-carrier currents inside and outside the P/N barrier region are able to be exactly defined and clearly calculated. Then, the stable continuity equations of the electron and hole currents are established to show the current conversion between minority- and majority-carriers inside the whole PN junction region. By analyzing all the conversion procedure, the J-V characteristics of a PN junction are obtained with good agreement to the experimental results, which are closely dependent on the minority-carrier lifetime and doping concentrations. Obviously, the study on this topic possesses referential significance to mechanically tuning the performance of piezoelectric PN junctions and piezotronics devices.