Résultat de la recherche
Si-Interdiffusion in heavily doped AIN-GaN-based quantum well intersubband photodetectors
We demonstrate the effect of rapid thermal annealing on heavily Si-doped AlN/GaN quantum wells. After 1000 °C annealing during 5, 10, and 20 min, the dominant effect was interdiffusion of Si rather than intermixing between the Al and Ga atoms. Both their original value and the magnitude of the changes after annealing reveal that intersubband absorption and photovoltage are related to two different optical transitions as follows: absorption occurs in the 1 to 2 intersubband transition, whereas photovoltage is due to a subsequent process from the 1 to 2 and the manifold of 2 to higher order transitions. © 2011 American Institute of Physics.
Intersubband spectroscopy probing higher order interminiband transitions in AlN-GaN-based superlattices
We investigate midinfrared intersubband photodetectors based on short-period AlN/GaN superlattices with different quantum well thicknesses. Band structure calculations, as well as optical transmission and photovoltage measurements, underline the importance of higher order interminiband transitions. In particular, it was found that optical transitions between the second and third minibands benefit from much larger electron displacements and oscillator strengths than those between the first and second minibands. Our results suggest that optical rectification is therefore much more efficient for devices based on a higher order interminiband transition.