“…On the other hand, co-existence in the LED active region of quantum wells (QWs) emitting at different wavelengths complicates operation of the devices. It was observed that the ratio of the emission intensities from different QWs is very sensitive to the operating current [11,12] and continuouswave versus pulsed power supply [13], temperature [10,14,15], active region design, i.e. the number of QWs of each type and their relative positions in the LED structure [10,13,16,17], thickness and doping (type and level) of the barrier separating different QWs [12,15,[18][19][20][21], as well as to the growth conditions of the monolithic LED structures and strain [22,23].…”