Selective area metalorganic molecular-beam epitaxy of GaN and the growth of luminescent microcolumns on Si/SiO2

We demonstrate the selective area growth of gallium nitride on patterned ${\mathrm{Si(111)/GaN/SiO}}_{\mathrm{2}}$ wafers by metalorganic molecular beam epitaxy using triethyl gallium as a Ga source. We show that such selective area deposition may be used to grow isolated microcolumns of GaN with lateral dimensions of tens of nanometers on ${\mathrm{Si/SiO}}_{\mathrm{2}}$ wafers. Via high resolution cathodoluminescence imaging we show that such microcolumn structures are highly luminescent inspite of a large surface to volume ratio, indicating that nonradiative recombination at free surfaces is not a significant issue in this system.