Critical layer thickness determination of GaN/InGaN/GaN double heterostructures

We report on the critical layer thickness of GaN/InxGa1-xN/GaN double heter ostructures in the composition range 0 <x <0.16. The evolution of the photo luminescence spectra and the electrical properties of the InxGa1-xN well we re monitored as its thickness was increased for a given % InN. Due to compr essive stress and possible quantum-size effects, the emission energy from t hin InGaN wells is blueshifted relative to thicker wells of a given % InN. The transition from the blueshifted emission of strained InGaN to redshifte d emission of relaxed InGaN is also accompanied by dramatic changes in film conductivity and mobility. The thickness at which the onset of relaxation occurs is deemed the critical layer thickness of the InxGa1-xN film. (C) 20 00 American Institute of Physics. [S0003-6951(00)02152-5].