In this work we discuss 3D selfconsistent solution of Poisson and Schrödinger equations for electrostatically formed quantum dot. 3D simulations give detailed insight into the energy spectrum of the device and allow us to find values of respective voltages ensuring given number of electrons in the dot. We performed calculations for fully 3D potential and apart from that calculations for the same potential separated into two independent parts, i.e. regarding to the plane of 2DEG and to the direction perpendicular to the meant plane. We found that calculations done for the two independent parts of the potential give good information about quantum dot properties and they are much faster compared to fully 3D simulations.
Strained layer InGaAs/GaAs SCH SQW (Separate Confinement Heterostructure Single Quantum Well) lasers were grown by Molecular Beam Epitaxy (MBE). Highly reliable CW (continuous wave) 980-nm, broad contact, pump lasers were fabricated in stripe geometry using Schottky isolation and ridge waveguide construction. Threshold current densities of the order of Jth ≈ 280 A/cm2 (for the resonator length L = 700 um) and differential efficiency η= 0.40 W/A (41%) from one mirror were obtained. The record wall-plug efficiency for AR/HR coated devices was equal to 54%. Theoretical estimations of above parameters, obtained by numerical modelling of devices were Jth ≈ 210 A/cm and η = 0.47 W/A from one mirror, respectively. Degradation studies revealed that uncoated and AR/HR coated devices did not show any appreciable degradation after 1500 hrs of CW operation at 35oC heat sink temperature at the constant optical power (50 mW) conditions.