A study of light emission of InAlGaN based multi quantum wells (with different well widths) has been performed by means of hydrostatic pressure and time resolved measurements. Both techniques are very sensitive to the presence of the large internal electric fields in hexagonal InGaN/GaN and GaN/AlGaN heterostructures. In the present studies, we found that independently of the quantum well width the pressure shift of the light emission energy and the photoluminescence decay time show almost constant values. This observation is interpreted as an evidence of the lack of built‐in electric field in the used quaternary quantum wells.