Field effective band alignment and optical gain in type-I Al0.45Ga0.55As/GaAs0.84P0.16 nano-heterostructures

The energy band alignment at the heterointerfaces plays a vital role in understanding the physics and optical processes such as optical gain or optical absorption in semiconductor opto-electronic devices. This paper reports the behavior of field effective energy band alignment followed by the behavior of probability density of the charge carriers in the respective bands of type-I Al0.45Ga0.55As/GaAs0.84P0.16 symmetric nano-scale-heterostructures. In addition, the optical gain of the structure within TE (transverse electric) and TM (transverse magnetic) modes under constant electric field applied is also simulated and analyzed. In order to simulate the optical gain of the structure, 4 × 4 diagonal k→.P→ Hamiltonian matrix is solved for the purpose of getting envelope functions associated with carriers, carrier densities, dispersion curves of the quantum well structure, transition matrix elements and finally the optical gain. On behalf of simulated results achieved, it is reported that the optical gain in TM mode is found much greater than that in TE mode which is opposite to usual trends. Moreover, the application of external electric field along the growth direction shows that the optical gain within TM mode and the wavelength both can be controlled by controlling the electric field applied. Thus, the nano-heterostructure can be tuned externally by the application of external electric field within the NIR (near infra red) region.