In GaN quantum dot is a promising optoelectronic material,which combines the advantages of low-dimensional and wide-gap semiconductors.The growth of In GaN quantum dots is still not mature,especially the growth by metal–organic–vapor phase epitaxy(MOVPE),which is challenge due to the lack of 、itin-situ monitoring tool.In this paper,we reviewed the development of In GaN quantum dot growth by MOVPE,including our work on growth of near-UV,green,and red In GaN quantum dots.In addition,we also introduced the applications of In GaN quantum dots on visible light emitting diodes.
Roughened surfaces of light-emitting diodes(LEDs)provide substantial improvement in light extraction efficiency.By preparing the self-assemble nanoporous Ni template through rapid annealing of a thin Ni film,followed by a low damage dry etching process,a p-side-up LED with a roughened surface has been fabricated.Compared to a conventional LED with plane surface,the light output of LEDs with nanoporous p-GaN surface increases up to 71%and 36%at applied currents of 1 mA and 20 mA,respectively.Meanwhile,the electrical characteristics are not degraded obviously after surface roughening.
In this paper,we simulate a new style vertical HVPE reactor by using computational fluid dynamics program FLUENT.In order to find the best parameter on the growth rate of Gallium nitride(GaN),we change the distance between the inlet and the substrate,GaCl and NH3 inlets,and also we add substrate rotation separately.With the increase of the distance between the substrate and the gas inlet,GaN deposition rate decreases and the uniformity becomes better.The results show that the optimal distance in this new-style vertical hydride vapour phase epitaxy(HVPE) system is 4 cm.Besides,as the distance between the GaCl inlet and the NH3 inlet changes,the uniformity of GaN deposition varies.Our findings indicate that the optimal distance is 3 cm.Furthermore,it is found that substrate rotation also affects the growth rate of GaN.
