to nucleate down onto the substrate and allowing for transport of reaction products out of the nanoscale features the height of the cylindrical openings i e the distance from the substrate interface to the top of the masking layer is preferably from about 5 nm to about 1000 nm more preferably from about 10 nm to about 500 nm even more preferably from about 25 nm to about 100 nm the dimension between individual nanopatterned features is from about 15 nm to about 25 nm more preferably from about 25 nm to about 75 nm even more preferably from about 75 nm to about 500 nm the thickness of the substrate 102 is typically 200 u03bcm to about 600 u03bcm the inorganic mask layer thickness ranges from about 5 nm to about 1000 nm more preferably from about 25 nm to about 200 nm even more preferably from about 50 nm to about 100 nm the gallium nitride film thickness measured from the bottom of the feature opening i e the substrate interface ranges from about 0 1 u03bcm to about 6 u03bcm more preferably from about 0 25 u03bcm to about 5 u03bcm even more preferably from about 0 5 u03bcm to about 5 u03bcm the inorganic mask layer 104 may comprise silicon oxide silicon nitride tungsten or any other material that does not react with gallium nitride it is preferred to use an inorganic mask layer 104 that is able to withstand microfabrication processes in the range of about 800 u00b0 c to about 1100 u00b0 c referring now.