InGaN nanorings and nanodots by selective area epitaxy

Abstract

An integrated process to fabricate controllable arrays of semiconductor nanorings and nanodots on patterned surfaces is presented. This approach is based on pattern transfer of nanopores to a SiO2 layer, followed by selective epitaxial growth of InGaN onto an underlying GaN substrate using metalorganic chemical vapor deposition. Using this approach, crystalline InGaN nanorings and nanodots ∼80nm in diameter have been grown on GaN surfaces. The formation mechanism of the nanorings and nanodots is described based on the initial stage of selective growth and restricted atom migration in a confined hole. Strong photoluminescence obtained at room temperature from the noncapped nanorings indicates strong confinement of the excitons in the nanostructures. This approach enables fabrication of dense, uniform arrays of epitaxial nanostructures and is potentially applicable to a variety of materials systems.

Effect of Aluminum Purity on the Pore Formation of Porous Anodic Alumina

“…9 These applications involve electrochemical deposition, 2,3 atomic layer deposition, 6,7 and chemical vapor deposition. 10 Porous alumina membrane formed by the anodization of aluminum consists of a close-packed array of hexagonal cells, each containing a cylindrical central pore. These pores are extended down to the barrier layer, which is a continuous, non-porous dielectric oxide layer between the pore bottom and the aluminum.…”

“…Most reports on the anodizing of aluminum use high-purity aluminum for improving the quality of porous alumina membranes. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] However, few studies have been conducted on the anodization of low-purity aluminum. [21][22][23][24][25][26][27][28][29] Fabrication of anodic alumina membranes from low-purity aluminum foil is not trivial and often requires specific conditions, different from those typically applied to the anodization of high-purity aluminum.…”

Analysis of nanopore arrangement and structural features of anodic alumina layers formed by two-step anodizing in oxalic acid using the dedicated executable software

“…To gain new properties of materials related to their nanometric size in at least one dimension, nanowires [2][3][4][5][6][7][8][9][10][11], nanotubes [12,13] and nanodots [14,15] made of various materials like metals and alloys [2-5, 14, 15], semiconductors [6,7], superconductors [8] and polymers [10][11][12][13] were obtained using various techniques, including electrochemical deposition [2][3][4][5][10][11][12], sol-gel technique [6,8], atomic layer deposition [14,15], and chemical vapor deposition [9]. Recently, fabrication of many devices based on anodic aluminum oxide (AAO) has been also reported [16][17][18][19].…”

Growth and Optical Properties of Highly Uniform and Periodic InGaN Nanostructures

“…We first reported InGaN nanodots and nanorings grown on patterned GaN surfaces by NSAE, in which the growth template is patterned by nanopatterns in the porous aluminum oxide. [30] However, long-range-ordered nanostructure arrays are hard to obtain because of the nature of the self-assembled porous aluminum oxide.Here, we describe the fabrication and optical properties of long-range-ordered InGaN nanostructures grown on GaN/ sapphire substrates by NSAE. In this work, dense periodic nanohole patterns with different hole diameters were defined by EBL and transferred to a SiO 2 layer, which serves as the growth template.…”

“…Our best result for the lateral nanodot size inhomogeneity was found to be as small as 3 %, [31] which is much smaller than those created using anodized alumina templates. [17,30] The diameters of the nanodots and nanorings vary from 50 to 100 nm, as defined by different pattern sizes on the SiO 2 template. As illustrated by the 3D views, different physical geometries were developed for different pattern sizes.…”