An engaging teaching method provides an equal learning opportunity for students on the often-arduous concepts in optoelectronics, which enhances involvement of minorities during a lecture session. Experiment-oriented instruction of topics combined with a dynamic and dialogue-based delivery of the lectures has showed increased participation from the class. Such experiments must be designed based on commonly used optoelectronic devices i.e. LEDs, to provoke interest among the learners. Furthermore, the students have to investigate non-trivial characteristics of such devices, e.g. measuring emission spectrum with a hand-held spectrometer, in groups of two-three. These would ensure a balanced learning opportunity among all the students.
We investigate mechanisms by which interaction of light and matter may be affected by electrons, and show how this can lead to optoelectronic devices with superior properties. In particular, confined cloud of electron gas allows sculpting a wave function that affects both emission and absorption of radiation, while its collective, plasmonic, excitation may be used for optical wave guiding, coupling and radiation. Such processes require much less energy and are much faster than classical kinetic energy-based charge transport in traditional electronics. Here we present thin-film photodetectors in which 2D electron and hole charges allow operation in hundreds of GHz, without applied bias, requiring a fraction of microwatt of optical power. The 2D channel can also be structured to provide the momentum change that is required for coupling to excitation at THz range. The confined charge is then used as a plate of (an unconventional) capacitor which changes states by a factor of >1000, in tens of fs, requiring atto-joules of energy which is also switchable by light. This opto-plasmonic capacitor finds application in threshold logic based neuromorphic systems. These thin-film devices are produced in bottom-up core-shell nanowire (CSNW) technology, resulting in resonant optical cavities whose properties are controlled by 2D and 1D charge plasma, with orders of magnitude increase in absorption and emission of light that leads to lasing at room temperature even without vertical structure. Since CSNWs can be grown on Si, they can be good candidate platforms for Photonic Integrated Circuits (PIC) and Silicon Photonics.
We present a high-performance short-wavelength infrared n-i-p photodiode, whose structure is based on type-II
superlattices with InAs/InAs1-xSbx/AlAs1-xSbx on GaSb substrate. At room temperature (300K) with front-side
illumination, the device shows the peak responsivity of 0.47 A/W at 1.6mm, corresponding to 37% quantum efficiency at
zero bias. At 300K, the device has a 50% cut-off wavelength of ~1.8mm. For −50mV applied bias at 300 K the
photodetector has dark current density of 9.6x10-5 A/cm2 and RxA of 285 Ω•cm2, and it revealed a detectivity of
6.45x1010 cm•Hz1/2/W. Dark current density reached to 1.3x10-8 A/cm2 at 200 K, with 36% quantum efficiency which
leads to the detectivity value of 5.66x1012 cm•Hz1/2/W.