Spectral and Angular Response

quantumex21.in : Spectral and Angular Response

Requires: S-Pisces/Quantum
Minimum Versions: Atlas 5.28.1.R

In this example, we simulate intersubband GaAs/AlGaAs n-type multiple quantum well infrared photodetector (QWIP). We optimized the material and geometrical aspects of the QWIP to tune the wavelength of its peak responsivity, and to eliminate all but one bound state per well.

At a voltage bias commonly found in experimental conditions for these systems, we calculate the optical gain, and estimate the radiative capture rate of the device. We confirm the radiative capture to be much slower than the known phonon-driven capture for such detectors.

Intersubband n-type QWIP detectors only operate at oblique incidence angles. We simulate the response of the detector for angles ranging from 0 to 80 degrees with respect to the normal, and close to the wavelength of peak response. The results take into account the coherent multiple reflections of radiation inside the active region thanks to the Transfer Matrix Method used.

We simulate the spectral response of the detector, obtaining the absorption and the generated photocurrent for a beam at 30 degrees with respect to the normal. The physical structure and material properties of the device allow only 1 bound state to exist. We set WELL.CNBS=2 in order to allow Atlas to search for up to two states, and we confirm in the output that only 1 state exists. This is why the bound-bound transition contribution to spontaneous emission is zero. A non-zero contribution would indicate the existence of multiple bound states, and therefore, degraded device performance.

Detailed description of models and corresponding parameters used in this simulation can be found directly in the input deck.

To load and run this example, select the Load button in DeckBuild > Examples. This will copy the input file and any support files to your current working directory. Select the Run button in DeckBuild to execute the example.