Abstract
The comparisons of the morphology, material property, and optical characteristics of a crack-free InGaN/GaN quantum-well light-emitting diode (LED) structure of completely coalesced overgrowth on an a-axis-oriented one-dimensional trench-patterned Si (110) substrate with the other two samples grown on flat Si (110) and Si (111) substrates are demonstrated. This sample on patterned Si (110) substrate shows the highest crystal quality, weakest tensile strain, largest internal quantum efficiency, strongest LED output intensity, lowest device resistance, and smallest spectral shift range in increasing injection current. The small spectral shift range indicates the weak quantum-confined Stark effect. The advantages of this sample are attributed to the small lattice mismatch between Si and GaN along the m-axis, the reduced thermal stress along the m-axis, and the minimized upward-propagating dislocation density. (C) 2013 AIP Publishing LLC.