TUNNELING EFFECT ON THE INTERSUBBAND OPTICAL-ABSORPTION IN QUANTUM-WELL STRUCTURES

The tunneling effect on the intersubband optical absorption in a quant um well structure subjected to an external electric field perpendicula r to the layers has been investigated theoretically, The analysis is b ased on the calculation of the intersubband transition rate by means o f Fermi's golden rule using expressions for the density of states, and the wave functions of the quasi-stationary energy levels inside the q uantum well obtained considering the tunneling of electrons. We find t hat the density of states consists of peaks with asymmetrical broadeni ng, which increase with the electric held and their positions correspo nd to the quasistationary levels inside the quantum well, and an expre ssion is obtained for the intersubband absorption coefficient as a fun ction of the photon energy. We applied these results to calculate the responsivity spectrum for a multiple quantum well infrared photodetect or. The theoretical results are compared with experimental data.