Effects of carrier gas on the properties of InGaN/GaN quantum well structures grown by MOCVD

In this paper we report on the influence of the carrier gas used during gro wth on the optical and microstructural properties of InxGa1-xN/GaN multi-qu antum well structures (L = 50 Angstrom, x = 0.15) grown by MOCVD. The sampl e grown with hydrogen carrier gas resulted in a luminescence spectrum that consisted of a single line (FWHM = 57 meV) whereas growth of the barrier ma terial using a nitrogen carrier gas results in luminescence spectra with FW HM in the range of 150 to 200 meV. The change in the optical properties cor relates with changes in the microstructural properties. The inferior qualit y of the samples grown using nitrogen carrier gas is thought to be due to t he increased density of growth nucleation sites formed during the growth pr ocess resulting in increased interface roughness and a progressive increase in the well thickness throughout the structures.