Growth and properties of blue/green InGaN/GaN MQWs on Si(111) substrates

InGaN/GaN multiple quantum wells (MQWs) were grown on highly tensile-strained GaN films on Si(111) substrate by metalorganic chemical vapor deposition. Due to the large difference of lattice constant and thermal expansion coefficient between GaN and Si, GaN growth on Si(111) substrate usually leads to an initially high dislocation density and cracks. We demonstrate low-dislocation-density and crack-free GaN films grown on Si(111) substrate by introducing an AIN/GaN strain-compensation layer and Si _xN _y, dislocation masking layer. Blue/green-emitting InGaN/GaN MQW heterostructures have been successfully grown on Si(111) substrates. Two sets of InGaN/GaN MQWs with different In solid composition and number of pairs grown between 820°C and 900°C were studied by high-resolution X-ray diffraction and photoluminescence spectroscopy. The emission wavelengths of InGaN MQW structures were significantly dependent on growth temperature.