7 research outputs found
Optical gain enhancement and wavefunction confinement tuning in AlSb/InGaAsP/GaAsSb heterostructures
Nano-imaging of intersubband transitions in van der Waals quantum wells
The science and applications of electronics and optoelectronics have been
driven for decades by progress in growth of semiconducting heterostructures.
Many applications in the infrared and terahertz frequency range exploit
transitions between quantized states in semiconductor quantum wells
(intersubband transitions). However, current quantum well devices are limited
in functionality and versatility by diffusive interfaces and the requirement of
lattice-matched growth conditions. Here, we introduce the concept of
intersubband transitions in van der Waals quantum wells and report their first
experimental observation. Van der Waals quantum wells are naturally formed by
two-dimensional (2D) materials and hold unexplored potential to overcome the
aforementioned limitations: They form atomically sharp interfaces and can
easily be combined into heterostructures without lattice-matching restrictions.
We employ near-field local probing to spectrally resolve and electrostatically
control the intersubband absorption with unprecedented nanometer-scale spatial
resolution. This work enables exploiting intersubband transitions with
unmatched design freedom and individual electronic and optical control suitable
for photodetectors, LEDs and lasers