Optical properties of potential-inserted quantum wells in the near infrared and Terahertz ranges

Abstract

We propose an engineering of the optical properties of GaAs/AlGaAs quantum wells using AlAs and InAs monolayer insertions. A quantitative study of the effects of the monolayer position and the well thickness on the interband and intersubband transitions, based on the extended-basis sp 3 d 5 s * tight-binding model, is presented. The effect of insertion on the interband transitions is compared with existing experimental data. As for intersubband transitions, we show that in a GaAs/AlGaAs quantum well including two AlAs and one InAs insertions, a three level {e1, e2, e3} system where the transition energy e3 − e2 is lower and the transition energy e2 − e1 larger than the longitudinal optical phonon energy (36 meV) can be engineered together with a e3 − e2 transition energy widely tunable through the TeraHertz range.

Photoelectrochemical water oxidation of GaP1−xSbx with a direct band gap of 1.65 eV for full spectrum solar energy harvesting

“…The inset shows the reciprocal space map around (224) illustrating the full relaxation state of GaP 0.67 Sb 0.33 (S x and S z are the projected coordinates in the right handed Cartesian, with the z axis parallel to the surface normal). 43 and the absence of intentional doping, the photocurrent of the GaP 0.67 Sb 0.33 grown on Si photoanode remains high compared to a reference n-doped GaP photoanode (see Fig. S7 in the ESI †) (with a much lower density of crystal defects).…”

“…For these states, bowing parameters are introduced to model the strong bowing of the G bandgap of 2.7 eV. 43 With a bowing parameter equal to 9.0 eV for the s-state and equal to 2.8 eV for the p-state, the experimental bandgap for GaP 0.67 Sb 0.33 is nicely reproduced.…”

Potential‐inserted quantum well design for quantum cascade terahertz lasers

“…This was actually implemented to shorten the operating wavelength of mid infrared QCLs . Recently, it has been theoretically shown that a three level system suitable for THz applications can be obtained in a single unbiased GaAs/AlAs QW by including multiple In and Al monolayer insertions inside the well . It was also shown that the envelope function approach (EFA), widely used in QCL modeling, fails to predict higher electron states energies in this particular case of very thin insertions, while the atomistic spds* tight‐binding (TB) model gave essentially perfect agreement with existing spectroscopic data.…”