Abstract
The enhanced Stark effect of the intersubband transitions in the three-coupled-quantum well (TCQW) structures has been demonstrated. By careful tailoring of layer thickness and composition, the 1→4 intersubband transition in the three-depth TCQW structure could have a very large Stark shift and could be used to fabricate a voltage-tunable midinfrared photodetector with a very large tunability. The tunability has been estimated by the self-consistent method. An AlInAs/GaInAs three-depth TCQW voltage-tunable photodetector with tuning ranges from 3 to 5 μm has been proposed.