Deep-level transient spectroscopy studies of electron and hole traps in n-type GaN homoepitaxial layers grown by quartz-free hydride-vapor-phase epitaxy

Kanegae, Kazutaka; Fujikura, Hajime; Otoki, Yohei; Konno, Taichiro; Yoshida, Takehiro; Horita, Masahiro; Kimoto, Tsunenobu; Suda, Jun

doi:10.1063/1.5098965

Cited by 42 publications

(20 citation statements)

References 27 publications

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“…[40][41][42][43] Furthermore, the acceptor nature of the main defect in carbon-doped bulk GaN was recently verified by the observation of p-type conductivity that was thermally activated with E A ¼ 1.02 eV. [41,44] The calculated acceptor level also agrees with the properties of the commonly observed H1 hole trap at E V þ 0.85-0.90 eV analyzed by deep level transient spectroscopy (DLTS) or minority carrier transient spectroscopy [45][46][47][48][49][50][51][52] and the . The transition at E max ¼ 2.2 eV denoted as YL1 is related to the C N acceptor level.…”

Section: Luminescence Of Single Carbon Defectssupporting

confidence: 53%

“…Especially for low unintentionally doped high-quality GaN grown by HVPE and MOCVD, a remarkable accordance between the overall carbon concentration determined by secondary ion mass spectrometry (SIMS) and the H1 hole trap concentration has been found. [51,52] 2.1.2. Blue Luminescence and the C N Donor Level: BL C Interestingly, HSE-based DFT calculations additionally predict a C N donor level at energies of E V þ 0.25-0.48 eV.…”

Section: Luminescence Of Single Carbon Defectsmentioning

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: Luminescence Of Single Carbon Defectssupporting

confidence: 53%

Section: Luminescence Of Single Carbon Defectsmentioning

confidence: 99%

Current Status of Carbon‐Related Defect Luminescence in GaN

Zimmermann

Beyer

Röder

et al. 2021

Physica Status Solidi (a)

View full text Add to dashboard Cite

show abstract

“…The C N (0/+) level is also thought to be identified by PL in HVPE GaN . Electrical measurement such as deep‐level transient spectroscopy (DLTS) provides more definitive understanding, and a variety of levels have been associated with carbon, including those for a deep acceptor, deep donor, and shallow donor . To date, most studies are performed on thin films with a limited range of carbon doping.…”

Section: Introductionmentioning

confidence: 99%

A Deep Carbon‐Related Acceptor Identified through Photo‐Induced Electron Paramagnetic Resonance

Paudel

Zvanut

Iwińska

et al. 2019

Physica Status Solidi (b)

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Herein, a carbon‐related point defect in thick free‐standing carbon‐doped GaN substrates grown by halide chemical vapor deposition is examined. Carbon is intentionally introduced to concentrations between 2 × 1017 and 1019 cm−3, and the number of point defects is proportional to the carbon concentration. The carbon center is detected using electron paramagnetic resonance spectroscopy after photo‐excitation with light greater than 2.8 eV. Simultaneous monitoring of the defect and a shallow donor confirms that the excitation occurs via removal of an electron from the deep carbon‐related acceptor and subsequent capture by the shallow donor. The study indicates that the defect level for the carbon defect is at least 0.7 eV above the valence band edge and therefore an excellent candidate for growth of semi‐insulating GaN.

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“…In our previous report, the defect state in α-NPB has been determined to be a defect state of the electron kind, which indeed exists in the site of 0.515 eV above the LUMO and whose function, in fact, can be seen as a LUMO trap according to research in this report. Sometimes there are also the concepts of electron trap and hole trap in the literature. − Electron trap means the trap is close to the conduction band, and hole trap means the trap is close to the valence band. Because they both exist in the energy space between the HOMO and LUMO, they are also included in the concept of the geometric trap.…”

Section: Resultsmentioning

confidence: 99%

Concepts of the HOMO and LUMO Traps from the Carrier Dynamics of Organic Semiconductor Isomers α-NPB and β-NPB

Zhang

Pang

et al. 2020

J. Phys. Chem. C

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The carrier dynamics of two isomers, α-NPB and β-NPB, were investigated through impedance spectroscopy based on the PSO algorithm. Their structure differences are only the N atom substitution sites on the naphthalene group. For α-NPB, the Nsubstitution is on the α-site of naphthalene, and for β-NPB, it is on the β-site. The carrier mobility of α-NPB is much higher than that of β-NPB. But AFM morphology shows that the film of β-NPB is smoother than that of α-NPB, which is in contrast with the common idea that, for a similar molecular structure, smoother film means a larger carrier mobility. In addition, the electron mobility of α-NPB is negatively related with the electrical field, but the hole mobility of α-NPB and the electron and hole mobilities of β-NPB are all positively related with an electrical field. In a common viewpoint, the carriers should be accelerated by an electrical field since they are charged carriers. Such phenomena have to be ascribed to a trap, but only a geometric trap is not enough for that. The geometric trap should have a similar effect to both electron and hole carriers, and it also cannot explain the higher mobility of α-NPB than β-NPB. Thus, all the experimental data show that there are some new kinds of traps existing in the OSCs. Because their site in energy space is close to the HOMO and LUMO of OSCs, they are noted as HOMO and LUMO traps. With the help of HOMO and LUMO traps, the experimental data can be easy to explain.

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Deep-level transient spectroscopy studies of electron and hole traps in n-type GaN homoepitaxial layers grown by quartz-free hydride-vapor-phase epitaxy

Cited by 42 publications

References 27 publications

Current Status of Carbon‐Related Defect Luminescence in GaN

Current Status of Carbon‐Related Defect Luminescence in GaN

A Deep Carbon‐Related Acceptor Identified through Photo‐Induced Electron Paramagnetic Resonance

Concepts of the HOMO and LUMO Traps from the Carrier Dynamics of Organic Semiconductor Isomers α-NPB and β-NPB

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