Facile Au-assisted epitaxy of nearly strain-free GaN films on sapphire substrates

Abstract

The nearly strain-free GaN films are epitaxially grown on Au-coated c-plane sapphire substrates via a self-patterned process.

Nonpolar Growth of GaN Films on Polar Sapphire Substrate Using Pulsed Laser Deposition: Investigation of Substrate Temperature Variation on the Quality of Films

“…The peaks can be attributed to Ga 2 p 3/2 and Ga 2 p 1/2 from GaN bonding, respectively. [ 45 ] Separation in between these peaks is observed at ≈28.84 ± 0.01 eV confirming the bonding in between Ga and N. [ 46 ] Due to the asymmetric nature of the O1s peak observed for all specimens (Figure 6), each spectra are deconvoluted into multiple peaks. The deconvoluted peaks are observed to be centered at 530.5 ± 0.2, 531.5 ± 0.2, and 532.8 ± 0.2 eV respectively.…”

“…The deconvoluted peaks are observed to be centered at 530.5 AE 0.2, 531.5 AE 0.2, and 532.8 AE 0.2 eV respectively. The peak positioned at 530.5 AE 0.2 eV can be attributed to the O-Al bond from the substrate used, that is, Al 2 O 3 , [45,47] whereas the peak observed at 531.5 AE 0.2 eV can be attributed to chemisorbed oxygen atom that may be present on the film surface. [48] The former peak observed herewith is mostly due to films that were exposed to air before analysis.…”

High Responsivity of Zero-Power-Consumption Ultraviolet Photodetector Using 2D-MoS2/i-GaN Vertical Heterojunction

“…The I – V curves of the i -GaN photodetector are given in Figure a. The dark current was found to be on the order of 10 –11 Å in the absence of external light at the applied voltage of 1 V. Upon the illumination of UV light with the wavelengths of 350 and 370 nm, the photocurrents were found to be increased by up to 2 orders of magnitude at the applied voltage of 1 V. The incident light is typically absorbed by a depletion region within the GaN when the bias is applied, where the electric field is high and the carriers are separated. , The separated carriers are then collected by the electrodes, leading to the generation of photocurrents. , The I – V characteristics of the 2D-MoS 2 / i -GaN device are given in Figure b. The dark current was increased compared to that of the i -GaN MSM photodetector but still maintained a low level on the order of 10 –10 Å at 1 V. The hybrid heterojunction device displayed a unique photo response when the UV lights were illuminated.…”

“…The dark current was found to be on the order of 10 −11 Å in the absence of external light at the applied voltage of 1 V. Upon the illumination of UV light with the wavelengths of 350 and 370 nm, the photocurrents were found to be increased by up to 2 orders of magnitude at the applied voltage of 1 V. The incident light is typically absorbed by a depletion region within the GaN when the bias is applied, where the electric field is high and the carriers are separated. 18,19 The separated carriers are then collected by the electrodes, leading to the generation of photocurrents. 20,21 The I−V characteristics of the 2D-MoS 2 /i-GaN device are given in Figure 4b.…”

Cathodoluminescent Analysis of Sapphire Surface Etching Processes in a Medium-Energy Electron Beam

“…A more detailed picture of the effect In the case of oxygen desorption, the outflow of positively charged aluminum atoms to negatively charged gold crystals can accelerate the decomposition (etching) of the sapphire surface. In addition, there have been recent studies [31] in which gold nanocrystals were used to obtain unstrained GaN films on sapphire.…”