| Popis: |
We investigated the behavior of the dark current (Id) in quantum well infrared photodetectors (QWIPs) in which the barrier layers were selectively doped instead of the well layers. Because the selective doping bends the conduction band (CB) edge in the portion of the barrier near the interface, the mechanism by which carriers in the wells can be emitted over the barriers, i.e. thermal emission and tunneling through this portion of the barrier, could be emphasized. We first confirmed that selectively doping the barrier layers clearly affects the Id-V characteristics. Then, by evaluating the activation energy obtained from the temperature dependence of Id, we found that the Poole-Frenkel emission (PFE) mechanism and the thermal-assisted tunneling (TAT)-like mechanism are dominant in the lower bias and higher bias regions, respectively. |
