A novel method of building a compositional non-uniformity in an InGaN layer grown on sapphire substrate by metalorganic chemical vapor deposition

In this paper, we demonstrate a novel method of building artificial indium composition non-uniformity in an InGaN layer. Ti and grooves are formed on the back of a sapphire substrate to lower the surface temperature during metalorganic chemical vapor deposition (MOCVD) growth. The photoluminescence (PL) peak emission wavelength becomes 18 nm longer in those areas where Ti or grooves are formed on the back surface. Deposition of Ti at the bottom of the grooves made the PL wavelength longer by 33-48 nm. The PL peak wavelength shifts with distance at a rate of about 9.4 nm/mm. This technique enables the production of novel devices that need non-uniform InGaN. layers such as light emitting diode (LED) arrays with different emission wavelengths.