“…This quenching of intensity is obviously small as compared with other reported data. In an undoped GaN continuous film, the intensity decreases by two orders of magnitude 36 , and a GaN epilayer on a Si(111) substrate exhibits a PL quenching by a factor of ~20 37 .Figure 5Evolution of the PL intensity against temperature measured in different samples. ( a ) Integrated PL intensity of different bands in p-GaN/(111)Si sample: red spheres correspond to the total spectral integration, purple dots, green diamonds and orange pentagons correspond to (FE + D 0 X), I 1 and I 2 related transitions, respectively.…”
Section: Resultsmentioning
confidence: 99%
“…This quenching of intensity is obviously small as compared with other reported data. In an undoped GaN continuous film, the intensity decreases by two orders of magnitude 36 , and a GaN epilayer on a Si(111) substrate exhibits a PL quenching by a factor of ~20 37 . Figure 5 Evolution of the PL intensity against temperature measured in different samples.…”
We investigate the optical properties of porous GaN films of different porosities, focusing on the behaviors of the excitonic features in time-integrated and time-resolved photoluminescence. A substantial enhancement of both excitonic emission intensity and recombination rate, along with insignificant intensity weakening under temperature rise, is observed in the porous GaN films. These observations are in line with (i) the local concentration of electric field at GaN nanoparticles and pores due to the depolarization effect, (ii) the efficient light extraction from the nanoparticles. Besides, the porosification enlarges the surface of the air/semiconductor interface, which further promotes the extraction efficiency and suppresses non-radiative recombination channels. Our findings open a way to increasing the emission efficiency of nanophotonic devices based on porous GaN.
“…This quenching of intensity is obviously small as compared with other reported data. In an undoped GaN continuous film, the intensity decreases by two orders of magnitude 36 , and a GaN epilayer on a Si(111) substrate exhibits a PL quenching by a factor of ~20 37 .Figure 5Evolution of the PL intensity against temperature measured in different samples. ( a ) Integrated PL intensity of different bands in p-GaN/(111)Si sample: red spheres correspond to the total spectral integration, purple dots, green diamonds and orange pentagons correspond to (FE + D 0 X), I 1 and I 2 related transitions, respectively.…”
Section: Resultsmentioning
confidence: 99%
“…This quenching of intensity is obviously small as compared with other reported data. In an undoped GaN continuous film, the intensity decreases by two orders of magnitude 36 , and a GaN epilayer on a Si(111) substrate exhibits a PL quenching by a factor of ~20 37 . Figure 5 Evolution of the PL intensity against temperature measured in different samples.…”
We investigate the optical properties of porous GaN films of different porosities, focusing on the behaviors of the excitonic features in time-integrated and time-resolved photoluminescence. A substantial enhancement of both excitonic emission intensity and recombination rate, along with insignificant intensity weakening under temperature rise, is observed in the porous GaN films. These observations are in line with (i) the local concentration of electric field at GaN nanoparticles and pores due to the depolarization effect, (ii) the efficient light extraction from the nanoparticles. Besides, the porosification enlarges the surface of the air/semiconductor interface, which further promotes the extraction efficiency and suppresses non-radiative recombination channels. Our findings open a way to increasing the emission efficiency of nanophotonic devices based on porous GaN.
“…At lower energies, the donor acceptor pair (DAP) emission at 3.182 eV is typical for as grown MBE-GaN samples. Room temperature PL measurements also illustrate the presence of blue and yellow peaks, which are due to the presence of gallium vacancies and deep level impurities [5].…”
We present in this work the characterization studies carried on GaN -thin films as processed by the Close Spaced Vapor Technique (CSVT), Laser Ablation (LA), and Molecular Beam Epitaxy (MBE), under particular growth parameters for each of the three techniques. The films characterization was performed by x-ray diffraction (X-RD), Photoluminescence (PL), Raman spectroscopy, optical transmission, energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). With these results an analysis of the samples was done, with an aim for a possible application of these thin films for PV -devices.
“…The s-shape evolution of photoluminescence (PL) energy with temperature is widely observed in important optoelectronic materials of bulk alloys and low-dimensional structures [1][2][3], covering a spectral range from ultra-violet to infrared [4,5]. Such behavior was well established to be due to localization, which may enhance radiative recombination as localized carriers are insensitive to non-radiative centers.…”
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