Direct evidence of hydrogen interaction with carbon: C–H complex in semi-insulating GaN

Wu, Shan; Yang, Xuelin; Shang, Qiuyu; Huang, Huayang; Shen, Jianhong; He, Xiao; Xu, Fujun; Wang, Xinqiang; Ge, Weikun; Shen, Bo

doi:10.1063/5.0010757

Cited by 14 publications

(7 citation statements)

References 33 publications

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“…Note that this is the sum of the binding energy of the C N À H i complex and the migration barrier of H þ . [113] Assuming the predicted binding energy of 1.2 eV, [105,108] the estimated migration barrier of 1.1-1.3 eV is in good agreement with migration barriers predicted for the Mg Ga -H [118] and C N À O N À H [108] complex dissociation. At room temperature, hydrogen returns to the complex, [108] thus explaining the restoration of the initial BL2 and YL1 intensities.…”

Section: Metastable Blue Luminescence Bl2 In Semi-insulating Gan: C N à H Isupporting

confidence: 69%

“…[105,108] A blue PL band around 3.0 eV labeled BL2 is often observed in highly resistive and semi-insulating GaN grown by MOCVD and HVPE. [90,108,[111][112][113][114] At low temperatures, BL2 can be distinguished from other PL bands in the blue spectral region by its high-energy fine structure that is highlighted in Figure 7.…”

Section: Metastable Blue Luminescence Bl2 In Semi-insulating Gan: C N à H Imentioning

confidence: 99%

“…[108,116] The spectral transformation of BL2 to YL1 indicates a conversion of the defect responsible for BL2 into the YL1 center. [90,108,[111][112][113][114] It was therefore proposed, [90,108] that BL2 originates from a complex of the YL1 center and hydrogen, which can be dissociated by a recombination-enhanced defect reaction. [117] Considering the association of YL1 to the C N acceptor level (cf., Section 2.1), BL2 is consequently attributed to the C N À H i complex.…”

Section: Metastable Blue Luminescence Bl2 In Semi-insulating Gan: C N à H Imentioning

confidence: 99%

“…After annealing the H concentration was reduced below the SIMS detection limit, whereas the concentration of other residual impurities was not affected. [113] Based on the beginning transformation at temperatures between 600 C and 700 C, those authors estimated E A ¼ 2.3-2.5 eV for the complex dissociation. Note that this is the sum of the binding energy of the C N À H i complex and the migration barrier of H þ .…”

Section: Metastable Blue Luminescence Bl2 In Semi-insulating Gan: C N à H Imentioning

confidence: 99%

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Current Status of Carbon‐Related Defect Luminescence in GaN

Zimmermann

Beyer

Röder

et al. 2021

Physica Status Solidi (a)

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Gallium nitride (GaN) has become an indispensable compound semiconductor due to its numerous applications in opto- [1,2] and microelectronic [3,4] devices. GaN-based light emitting diodes and laser diodes show higher efficiencies than competing materials and, by alloying with Al or In, the bandgap can cover both the visible and UV spectral range. [5] In addition, AlGaN/GaN heterostructures lead to the formation of a 2D electron gas (2DEG) at the AlGaN/GaN interface, which enables high-frequency switching devices. [6,7] Furthermore, due to the large breakdown voltage and thermal stability, GaN is the perfect candidate for high-power applications. [8,9] As a prerequisite for GaN-based power electronic devices, highly insulating buffers are required. [10,11] Here, carbon doping plays a major role to compensate for donor impurities, which occur even in nominally undoped GaN films. However, the role of carbon-related defects in heterojunction field effect transistors is multiple. They were shown to play a major role in the buffer transport mechanisms generally [12] and to contribute to current collapse [13,14] as well as a dynamical shift of the threshold voltage [11,15] in the devices.Advancements in the field of GaN growth resulted in bulk material of improved structural quality, often with dislocation densities below 10 6 cm À2 . [16,17] As a consequence, the influence of point defects as a limiting factor of device performance is gaining importance. [18][19][20] Therefore, a better understanding of point defects in GaN is required to improve device performance further and to control unwanted side effects.To study optically active point defects in semiconductors, photoluminescence (PL) is one of the experimental techniques most frequently used. The impact of carbon on the luminescence properties is, without doubt, one of the most debated subjects related to point defects in GaN. Although those discussions reach back more than 40 years, [21] considerable progress in the understanding of carbon-related point defect levels was made in the last decade.Two main factors greatly improved the understanding of carbon-related defect levels in GaN. On one hand, the implementation of hybrid functionals in density functional theory (DFT) accounts for carrier localization at acceptor species. This led to vast changes in the predicted energy values of charge state

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Section: Metastable Blue Luminescence Bl2 In Semi-insulating Gan: C N à H Isupporting

confidence: 69%

Section: Metastable Blue Luminescence Bl2 In Semi-insulating Gan: C N à H Imentioning

confidence: 99%

Section: Metastable Blue Luminescence Bl2 In Semi-insulating Gan: C N à H Imentioning

confidence: 99%

Section: Metastable Blue Luminescence Bl2 In Semi-insulating Gan: C N à H Imentioning

confidence: 99%

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Current Status of Carbon‐Related Defect Luminescence in GaN

Zimmermann

Beyer

Röder

et al. 2021

Physica Status Solidi (a)

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“…Recent reports further clarify the origin of the BL2 band in GaN. Wu et al [ 4 ] demonstrated that annealing at 1000 °C for 1 h of semi‐insulating GaN grown by MOCVD results in the disappearance of the BL2 band and an increase in the YL1 band. These results supported the hypothesis that the C N H i complex and isolated C N cause the BL2 and YL1 bands.…”

Section: Introductionmentioning

confidence: 99%

Stability of the C_NH_i Complex and the Blue Luminescence Band in GaN

Reshchikov

Andrieiev

Vorobiov

et al. 2021

Physica Status Solidi (b)

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Point defects in GaN affect the properties of the material and the performance of GaN-based devices. Photoluminescence (PL) is an efficient, nondestructive tool in studying point defects in semiconductors, [1] yet still, the assignments of several PL bands in GaN are lacking or unreliable. First-principles calculations help identify the defects associated with particular PL bands, and in return accurate experimental results provide unique information for validation of theoretical methods. In this study, we systematically investigated the carbon-hydrogen complex (C N H i ) in GaN using the combination of experimental and theoretical methods.A blue luminescence (BL) band with a maximum at 2.9-3.0 eV is often observed in PL spectra from GaN, especially from layers grown by metal-organic chemical vapor deposition (MOCVD) technique. [1] In undoped n-type GaN samples, the BL band with a maximum at 2.9 eV and the zero-phonon line (ZPL) at 3.10 eV (labeled BL1) appears due to contamination of GaN with Zn during growth. The BL1 band is caused by transitions via the Zn Ga acceptor with the À/0 level at 0.40 eV above the valence band. In other samples (usually highly resistive), a similar BL band (labeled BL2) appears with a maximum at about 3.0 eV and the ZPL at 3.33 eV. The characteristic feature of the BL2 band is its gradual disappearance under UV illumination at low temperatures, known as PL bleaching. The BL2 bleaching is accompanied by the rise in the yellow band with a maximum at 2.2 eV (the YL1 band). [1] We proposed earlier that the C N H i complex may be the origin of the BL2 band in GaN, and dissociation of this complex under UV light produces isolated C N defects responsible for the YL1 band. [2,3] Recent reports further clarify the origin of the BL2 band in GaN. Wu et al. [4] demonstrated that annealing at 1000 C for 1 h of semi-insulating GaN grown by MOCVD results in the disappearance of the BL2 band and an increase in the YL1 band. These results supported the hypothesis that the C N H i complex and isolated C N cause the BL2 and YL1 bands. The reduction of the H concentration below the detection limit after annealing was directly confirmed by secondary-ion mass spectrometry (SIMS) measurements. By repeating annealing at temperatures from 600 to 1000 C with an increment of 100 C, the authors of that paper observed that the BL2 band disappears between 600 and 800 C and estimated the activation energy of the complex decomposition as 2.3-2.5 eV. The dissociation of the C N H i complexes in Mg-doped GaN grown by MOCVD after annealing at 700 C in nitrogen ambient was also observed from analysis of infrared absorption peaks attributed to vibrational modes of this complex. [5] The dissociation of the H-containing complexes in GaN and the diffusion of hydrogen in n-and p-type GaN have attracted significant attention in the past. [6] The most studied case of the dissociation of H-containing complexes in GaN is the behavior of Mg-doped GaN grown by MOCVD. Nakamura et al. [7] demonstrated that after thermal annealing i...

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On the Origin of the Yellow Luminescence Band in GaN

Reshchikov

2022

Physica Status Solidi (b)

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The yellow luminescence (YL) band with a maximum at 2.2 eV is the dominant defect‐related luminescence in unintentionally doped GaN. The discovery of the mechanism responsible for this luminescence band and related defects in GaN took many years. Eventually, a consensus has been reached that the CN acceptor is the source of the YL band (the YL1 band) in GaN samples grown by several techniques. Previously suggested candidates, such as VGa, VGaON, CNON, and CNSiGa, should be discarded. At the same time, other defects (such as the VN, BeGa, and CaGa) may cause luminescence bands with positions and shapes not much different from the YL1 band. In GaN containing high concentrations of gallium vacancies, oxygen, and hydrogen, complexes containing these species may also contribute in the red–yellow part of the photoluminescence spectrum. The main controversies related to the YL band are resolved.

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Direct evidence of hydrogen interaction with carbon: C–H complex in semi-insulating GaN

Cited by 14 publications

References 33 publications

Current Status of Carbon‐Related Defect Luminescence in GaN

Current Status of Carbon‐Related Defect Luminescence in GaN

Stability of the C_NH_i Complex and the Blue Luminescence Band in GaN

On the Origin of the Yellow Luminescence Band in GaN

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Direct evidence of hydrogen interaction with carbon: C–H complex in semi-insulating GaN

Cited by 14 publications

References 33 publications

Current Status of Carbon‐Related Defect Luminescence in GaN

Current Status of Carbon‐Related Defect Luminescence in GaN

Stability of the CNHi Complex and the Blue Luminescence Band in GaN

On the Origin of the Yellow Luminescence Band in GaN

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Stability of the C_NH_i Complex and the Blue Luminescence Band in GaN