ABSTRACT
The intersubband transition mechanism for the bound-to-miniband quantum well infrared photodetectors (QWIPs) is due to the electron transition from the highly populated ground bound state to the miniband states inside the quantum well/superlattice barrier layers followed by the coherent and resonant tunneling conduction via the global miniband states. QWIPs based on intersub-band transitions have been extensively investigated for a wide variety of long wavelength infrared detection and focal plane array image sensor applications. Most of the QWIPs are fabricated from III-V semiconductor materials grown by using molecular beam epitaxy and metalorganic chemical vapor deposition techniques. The main advantage of intersubband transition QWIPs lies in the fact that they can be fabricated from the more mature III-V semiconductor material systems that have fewer growth and processing problems than that of HgCdTe material to achieve monolithic integration of QWIPs with readout circuits on the same chip. A majority of the studies on QWIPs so far have been focused on GaAs/AlGaAs material system.
