Effect of polarization on the performance of ZnO/MgZnO quantum cascade detector

The impact of polarization effect on the performance of ZnO/MgZnO quantum cascade detector (QCD) is investigated with different scattering mechanisms taken into account. The energy band structure and wave functions are achieved by self-consistent calculation of Schrodinger-Poisson equations considering the spontaneous and piezoelectric polarization effects. The polarization field in the well or barrier of the QCD is obtained by assuming continuity of the displacement vector and the electronic transport is determined by piezoelectric polarization induced piezoelectric scattering, LO-phonon scattering and some other scattering mechanisms. The results show that the polarization charges at the interface make a significant contribution to the confining potential, which reduces the dark current, and increases the detectivity. The peak responsivity drops only 6.37% from 57 to 400 K without apparent redshift and the detectivity can be significantly improved by increasing doping concentration. This work is beneficial for the ZnO/MgZnO QCD design.