Comparison of optical properties between GaN and InGaN quantum wells

We report on the experimental determination of the photoluminescence mechan ism in a set of In0.2Ga0.75N quantum wells. Instead of studying the photolu minescence for different In contents, we have investigated it as a function of the quantum well width in combination with a similar study performed on GaN quantum wells. In this way we show that the photoluminescence is not c oming from quantum dots in the quantum well but from the quantum well itsel f under the influence of an internal electric field induced by strain.