Optical transition in infrared photodetector based on V-groove Al[sub 0.5]Ga[sub 0.5]As/GaAs multiple quantum wire.

Photoconductors based on V-grooved Al[sub 0.5]Ga[sub 0.5]As/GaAs multiple quantum wires (QWR) were fabricated. The geometric structure of the QWR was carefully characterized by transmission electron microscopy and spatially resolved microphotoluminescence measurements. Infrared response at 9.2 μm is observed from the photocurrent spectrum measured at 80 K. It is attributed as the intersubband transition in the quantum wire region. Due to the effective quantum confinement from the two (111)-surfaces forming the V groove, the overlapping between the ground state in the QWR and the one in the vertical quantum well is very small. This explains the weak photocurrent signal from the QWR photodetector. Theoretical design for a better wave function overlapping and optical coupling is outlined from the analysis of two-dimensional spatial distributions of the wave functions. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]