Strain-balanced InGaN/GaN multiple quantum wells

InGaN/GaN multiple quantum well (MQW) structures suffer from a high amount of compressive strain in the InGaN wells and the accompanied piezoelectric field resulting in both a blue shift in emission and a reduction of emission intensity. We report the growth of InxGa1-xN/GaN "strain-balanced" multiple quantum wells (SBMQWs) grown on thick InyGa1-yN templates for x> y by metal organic chemical vapor deposition. SBMQWs consist of alternating layers of InxGa(1-x)N wells and GaN barriers under compressive and tensile stress, respectively, which have been lattice matched to a thick InyGa1-yN template. Growth of the InyGa1-yN template is also detailed in order to achieve thick, relaxed InyGa1-yN grown on GaN without the presence of V-grooves. When compared to conventional InxGa1-xN/GaN MQWs grown on GaN, the SBMQW structures exhibit longer wavelength emission and higher emission intensity for the same InN mole fraction due to a reduction in the well strain and piezoelectric field. By matching the average lattice constant of the MQW active region to the lattice constant of the InyGa1-yN template, essentially an infinite number of periods can be grown using the SBMQW growth method without relaxation-related effects. SBMQWs can be utilized to achieve longer wavelength emission in light emitting diodes without the use of excess indium and can be advantageous in addressing the "green gap." (C) 2014 AIP Publishing LLC.