Relationship between structure characteristic and blue luminescence in unintentional doped GaN layers

Li, Shuti; Jiang, Fengyi; Han, Guang‐Fan; Wang, Li; Xiong, Chuanbing; Peng, Xuexin; Mo, Hunlan

doi:10.1016/j.mseb.2005.02.067

Cited by 7 publications

(6 citation statements)

References 24 publications

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“…The formation of a BL band is due to the recombination of the free electron in a conduction band (around room temperature) to relatively deep acceptor (e-A luminescence) levels. The observation of BL is typical for MOCVD grown GaN layers [18] and is related to some impurities coming from an MO source (Mg, Zn). The BL is dominated by the involvement of oxygen, carbon, and hydrogenated gallium vacancies in n-type GaN [20] and is associated with some metastable defects [21].…”

Section: Resultsmentioning

confidence: 91%

“…Another emission band, called BL, which is centered at 2.83 eV in our case, sometimes appears in unintentionally doped GaN films at room temperature [17][18][19] and is related to the crystalline quality. The formation of a BL band is due to the recombination of the free electron in a conduction band (around room temperature) to relatively deep acceptor (e-A luminescence) levels.…”

Section: Resultsmentioning

confidence: 99%

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Analysis of defect related optical transitions in biased AlGaN/GaN heterostructures

Bengi

Li̇şesi̇vdi̇n

Kasap

et al. 2010

Materials Science in Semiconductor Processing

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The optical transitions in AlGaN/GaN heterostructures that are grown by metalorganic chemical vapor deposition (MOCVD) have been investigated in detail by using Hall and room temperature (RT) photoluminescence (PL) measurements. The Hall measurements show that there is two-dimensional electron gas (2DEG) conduction at the AlGaN/GaN heterointerface. PL measurements show that in addition to the characteristic near-band edge (BE) transition, there are blue (BL) and yellow luminescence (YL) bands, free-exciton transition (FE), and a neighboring emission band (NEB). To analyze these transitions in detail, the PL measurements were taken under bias where the applied electric field changed from 0 to 50 V/cm. Due to the applied electric field, band bending occurs and NEB separates into two different peaks as an ultraviolet luminescence (UVL) and Y4 band. Among these bands, only the yellow band is unaffected with the applied electric field. The luminescence intensity change of these bands with an electric field is investigated in detail. As a result, the most probable candidate of the intensity decrease with an increasing electric field is the reduction in the radiative lifetime. © 2010 Elsevier Ltd. All rights reserved

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Section: Resultsmentioning

confidence: 91%

Section: Resultsmentioning

confidence: 99%

Analysis of defect related optical transitions in biased AlGaN/GaN heterostructures

Bengi

Li̇şesi̇vdi̇n

Kasap

et al. 2010

Materials Science in Semiconductor Processing

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“…In fact, the origin of the BL band of GaN is still in dispute. On one hand, Li et al suggested that the BL band is the transition from the free electron to acceptor levels through double-crystal X-ray diffraction and PL measurements [ 22 ]. On the other hand, Reshchikov et al proposed that the BL band was attributed to a V Ga -related complex [ 23 ], such as V Ga -O N complex whose energy level was at 0.8 eV above the valence-band edge [ 24 ].…”

Section: Resultsmentioning

confidence: 99%

Carbon-Related Defects as a Source for the Enhancement of Yellow Luminescence of Unintentionally Doped GaN

et al. 2018

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Yellow luminescence (YL) of unintentionally doped GaN (u-GaN) peaking at about 2.2 eV has been investigated for decades, but its origin still remains controversial. In this study, ten u-GaN samples grown via metalorganic chemical vapor deposition (MOCVD) are investigated. It is observed from the room temperature (RT) photoluminescence (PL) measurements that the YL band is enhanced in the PL spectra of those samples if their MOCVD growth is carried out with a decrease of pressure, temperature, or flow rate of NH3. Furthermore, a strong dependence of YL band intensity on the carbon concentration is found by secondary ion mass spectroscopy (SIMS) measurements, demonstrating that the increased carbon-related defects in these samples are responsible for the enhancement of the YL band.

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“…The impurities and native defects are not yet well established, but the most probable impurity type is the Si on Ga sites (Si Ga ) [40] and the most probable native defects are the gallium vacancy (V Ga ) for the n-type GaN and the nitrogen vacancy (V N ) for the p-type GaN [41]. The broad BL band is a characteristic of MOCVD grown undoped or unintentionally doped GaN layers [42], and is attributed to the transition from the conduction band to the deep acceptor (e-A) levels. The most probable candidates of this transition are intrinsic defects such as dislocations and low angle grain boundaries, metastable defects such as the Zn and Mg acceptor levels due to the system contamination (MO source impurities) and carbon and oxygen on the Ga sites (C Ga and O Ga ) [42][43][44].…”

Section: Resultsmentioning

confidence: 99%

“…The broad BL band is a characteristic of MOCVD grown undoped or unintentionally doped GaN layers [42], and is attributed to the transition from the conduction band to the deep acceptor (e-A) levels. The most probable candidates of this transition are intrinsic defects such as dislocations and low angle grain boundaries, metastable defects such as the Zn and Mg acceptor levels due to the system contamination (MO source impurities) and carbon and oxygen on the Ga sites (C Ga and O Ga ) [42][43][44]. Another broad YL band is attributed to the transition of electron from the conduction band to the deep acceptor, from the shallow or deep donor to the deep or shallow acceptor, from the deep donor to the valance band, crystalline defects, and the residual impurities due to the system contamination [45][46][47][48][49][50].…”

Section: Resultsmentioning

confidence: 99%

Characterization of an AlN buffer layer and a thick-GaN layer grown on sapphire substrate by MOCVD

et al. 2010

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An AlN buffer layer and a thick-GaN layer for high-electron-mobility transistors (HEMTs) were grown on sapphire substrate by metal-organic chemical vapor deposition (MOCVD). The structural and morphological properties of the layers were investigated by high resolution X-ray diffraction (HRXRD) and atomic force microscopy (AFM) techniques. The optical quality of the thick-GaN layer was also evaluated in detail by a photoluminescence (PL) measurement. It was found that the AlN buffer layer possesses high crystal quality and an atomically flat surface with a root-mean-square (rms) roughness of 0.16 nm. The screw-and edge-type dislocation densities of the thick-GaN layer were determined as 5.4 9 107 and 5.0 9 109 cm-2 by means of the mosaic crystal model, respectively. It was observed that the GaN layer has a smooth surface with an rms of 0.84 nm. Furthermore, the dark spot density of the GaN surface was estimated as 6.5 9 108 cm-2 over a scan area of 4 μm2. © Springer Science+Business Media, LLC 2010

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Relationship between structure characteristic and blue luminescence in unintentional doped GaN layers

Cited by 7 publications

References 24 publications

Analysis of defect related optical transitions in biased AlGaN/GaN heterostructures

Analysis of defect related optical transitions in biased AlGaN/GaN heterostructures

Carbon-Related Defects as a Source for the Enhancement of Yellow Luminescence of Unintentionally Doped GaN

Characterization of an AlN buffer layer and a thick-GaN layer grown on sapphire substrate by MOCVD

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