Unambiguous relationship between photoluminescence energy and its pressure evolution in InGaN/GaN quantum wells

We have studied pressure dependence of photoluminescence in InGaN/GaN quantum wells (QWs). Universal dependence of the pressure coefficients dEPL/dp on the emission energy, at ambient pressure. EPL, in polar InGaN/GaN QWs has been found. This dependence is fulfilled for structures having different QWs, different composition of InGaN, and growth method. Calculations performed using k · p method combined with theory of elasticity and piezoelectricity support the experimental finding when an assumption on strain dependence of piezoelectric coefficients in nitride semiconductors is applied. We have also performed measurements of semipolar () InGaN/GaN QWs with different In-content. The same univocal dependence between EPL and dEPL/dp realized for polar structures has been also found in the studied semipolar QWs.