Microstructure and optical properties of nanocrystalline GaN embedded in silica matrix

Inorganic Dispersed-Phase Composites by Sol-Gel Processing: An Update

“…The most recent investigation [122] in this area indicates the following features. Though the preparative procedure was similar to that described by Qiu et al [121], the "silica" matrix in this case indicated the presence of Si-O, Si-N and Si-N-O bonds, so that it could be described as a nitrogen-bonded or -doped silica matrix. Further, the GaN nanoparticles (2-12 nm) crystallized at atmospheric pressure as a mixture of hexagonal and cubic polymorphs, the latter being generally obtainable at high pressures.…”

“…Examples of confinement of GaN particles in a rigid matrix by sol-gel processing are apparently rather rare [121,122]. Qiu et al [121] reported synthesis of 3-8 nm hexagonal GaN particles dispersed in a silica matrix through heat-treatment of the gel matrix composites at 800 o -900 o C under a constant flow of NH 3 . Room temperature PL spectra showed a near band edge emission at 390 nm that underwent no shift as a function of particle size.…”

Growth behavior of hexagonal GaN on Si(100) and Si(111) substrates prepared by pulsed laser deposition

“…This blue shift can be attributed to the crystallite size effect. 27,28) Moreover, the blue shift of the NEB peak was also explained by the stress generated in the GaN film with increasing total thickness. 29,30) It also confirms that the GaN film grown on Si(111) exhibits a full width at half-maximum (FWHM) of 2.47 meV on PL spectra, which is more than 1.25 times smaller than the 3.08 meV observed for GaN grown on a Si(100) substrate.…”

Optical properties of Si-doped GaN nanocrystals in SiO2/GaN/SiO2thin film structure

“…It may be noted that we did not consider the absorption due to surface traps and other impurities in our calculation as pointed out by Sekikawa et al [27]. The theoretically simulated absorbance spectra for GaN nanostructured films were obtained by using equations ( 6) and (11) and are shown in figure 5. The amount of optical loss due to scattering effect could be easily estimated from equation (12).…”

“…systems have become the subject of various experimental and theoretical research [10][11][12]. Most researchers have been interested in the synthesis of nanocrystalline III-V semiconductors in thin film form [13][14][15] in which voids among the nanocrystallites acted as the insulating medium between two adjacent nanocrystallites.…”