A method of forming an optoelectronic semiconductor device involves providing an amorphous substrate. A transparent and conductive oxide layer is deposited on the amorphous substrate. The transparent and conductive oxide layer is annealed to form an annealed transparent and conductive oxide layer having a cubic-oriented and/or rhombohedral-oriented surface. A nanorod array is formed on the cubic-oriented and/or rhombohedral-oriented surface of the annealed transparent and conductive oxide layer. The annealing of the transparent conductive oxide layer and the formation of the nanorod array are performed using molecular beam epitaxy (MBE). The nanorods of the nanorod array comprise a group-III material and are non-polar.