Performance improvement of AlN/GaN-based intersubband detectors thanks to quantum dot active regions

Since the operating mode of 1.55 µm AlN/GaN-based intersubband photodetectors is based on optical rectification, both the excited state lifetime and the lateral displacement of the carriers play an important role for performance optimization. We thus show here results of an improved detector generation based on a novel type of active region. Thanks to the use of quantum dots instead of quantum wells, a factor of 60 could be gained in terms of maximum responsivity. In addition, the maximum performance was achieved at a considerably higher temperature of 160 K instead of 80 K as typically seen for quantum wells

Photodetectors based on intersubband transitions using III-nitride superlattice structures

We review our recent progress on the fabrication of near-infrared photodetectors based on intersubband transitions in AlN/GaN superlattice structures. Such devices were first demonstrated in 2003, and have since then seen a quite substantial development both in terms of detector responsivity and high speed operation. Nowadays, the most impressive results include characterization up to 3 GHz using a directly modulated semiconductor laser and up to 13.3 GHz using an ultra-short pulse solid state laser