Properties of C‐doped GaN

Lesnik, A. G.; Hoffmann, Marc P.; Fariza, Aqdas; Bläsing, J.; Witte, Hartmut; Veit, Peter; Hörich, Florian; Berger, Christoph; Hennig, Jonas; Dadgar, A.; Strittmatter, A.

doi:10.1002/pssb.201600708

Cited by 37 publications

(26 citation statements)

References 48 publications

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“…Other details of these samples, including growth conditions and the results of initial characterization can be found in Ref. 23 -3 , even though the concentration of free electrons is lower than 10 18 cm -3 in some of these samples. Fig.…”

Section: A Samplesmentioning

confidence: 99%

Two charge states of the CN acceptor in GaN: Evidence from photoluminescence

et al. 2018

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We have found a new photoluminescence (PL) band with unusual properties in GaN. The blue band, termed as the BL C band, has a maximum at about 2.9 eV and an extremely short lifetime (shorter than 1 ns for a free electrons concentration of about 10 18 cm-3). The electron-and holecapture coefficients for this defect-related band are estimated as 10-9 and 10-10 cm 3 /s, respectively. The BL C band is observed only in GaN samples with relatively high concentration of carbon impurity, where the yellow luminescence (the YL1 band) with a maximum at 2.2 eV is the dominant defect-related PL. Both the YL1 and BL C bands likely originate from the C N defect, namely from electron transitions via the −/0 and 0/+ thermodynamic transition levels of the C N. BL C band appears only at high excitation intensities in n-type GaN samples co-doped with Si and C, and it can be found in wide range of excitation intensities in semi-insulating (presumably ptype) GaN samples doped with C. The properties and behavior of the YL1 and BL C bands can be explained using phenomenological models and first-principles calculations.

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Section: A Samplesmentioning

confidence: 99%

Two charge states of the CN acceptor in GaN: Evidence from photoluminescence

et al. 2018

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“…of knocking-in the surface contaminants into material volume during sputtering with a primary ion beam. In MOCVD-grown GaN samples, these "tails" of impurity concentrations from the surface to bulk are typically short (less than 50 nm) 7,13,14 . However, in HVPE-grown GaN, the tails of Si, O, C, and H are typically longer (200-500 nm) 8,10 .…”

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confidence: 99%

Determination of the concentration of impurities in GaN from photoluminescence and secondary-ion mass spectrometry

Reshchikov

Vorobiov

Andrieiev

et al. 2020

Sci Rep

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photoluminescence (pL) was used to estimate the concentration of carbon in Gan grown by hydride vapor phase epitaxy (HVPE). The PL data were compared with profiles of the impurities obtained from secondary ion mass spectrometry (SiMS) measurements. comparison of pL and SiMS data has revealed that apparently high concentrations of C and O at depths up to 1 µm in SIMS profiles do not represent depth distributions of these species in the Gan matrix but are rather caused by post-growth surface contamination and knocking-in impurity species from the surface. in particular, pL analysis supplemented by reactive ion etching up to the depth of 400 nm indicates that the concentration of carbon in nitrogen sites is below 2-5 × 10 15 cm −3 at any depth of Gan samples grown by HVpe. We demonstrate that pL is a very sensitive and reliable tool to determine the concentrations of impurities in the Gan matrix.GaN is a key material in modern solid-state lighting technology. The investigation and identification of point defects in GaN is very important, with immediate technology relevance to longer lifetime of light-emitting devices. Photoluminescence (PL) is a powerful tool for investigation of point defects in GaN 1 . Only few point defects in unintentionally doped GaN are well understood and reliably identified. One of them is the C N defect with the −/0 and 0/ + thermodynamic transition levels at 0.916 eV and ~0.3 eV, respectively, above the valence band 2-5 . This defect is responsible for the yellow luminescence (YL1) band with a maximum at 2.2 eV and zero phonon line (ZPL) at 2.59 eV in n-type GaN. Transitions via the 0/ + level of this defect can be observed as the blue luminescence (BL C ) band with a maximum at 3.3 eV at high excitation intensity 4 . The YL1 band is commonly observed in n-type GaN layers grown by metalorganic chemical vapor deposition (MOCVD), where the concentration of unintentionally introduced carbon is usually in the range of 10 16 -10 18 cm −3 , depending on growth conditions 6,7 . Undoped or Si-doped GaN samples grown by hydride vapor phase epitaxy (HVPE) contain much less carbon (10 15 -10 16 cm −3 ) 8-11 , yet still the YL1 band may be strong in these samples due to high hole-capture cross-section for the C N defects 12 .We have recently demonstrated 12 that PL can be used for determination of concentrations of defects responsible for PL bands. However, the concentrations of impurities found from PL were inconsistent with the concentrations found from secondary-ion mass spectrometry (SIMS) analysis in that study. Comparison of these two techniques is complicated by the following ambiguity. SIMS measurements provide depth profiles of impurity concentrations regardless of positions of impurity species (lattice sites or precipitations), whereas PL signal, excited with above-bandgap light, is collected from impurity atoms at lattice sites in the near-surface region (roughly, top 0.4 µm layer in GaN). The problem is that close to the surface, where PL is collected, very high concentrations of carbon an...

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“…The intensity of C 1s is found to increase as we increase the sensitivity of the measurement towards GaN surface while O 1s signal shows marginal changes with increased surface sensitivity. This suggests an increase in the compensation of free electrons with the increase of carbon concentration at the top GaN surface, depicting the semi‐insulating nature or HR‐GaN surface …”

Section: Resultsmentioning

confidence: 96%

“…The intentional/unintentional doping of suitable species can cause compensation of free electrons in the inherently negatively charged defects rich GaN to form semi‐insulating or highly resistive GaN (HR‐GaN). This may lead to a reduction in the leakage current by several orders due to the shift in the Fermi level toward midgap position, thereby, facilitating a prompt lateral current transportation …”

Section: Introductionmentioning

confidence: 99%

Long‐Term, High‐Voltage, and High‐Temperature Stable Dual‐Mode, Low Dark Current Broadband Ultraviolet Photodetector Based on Solution‐Cast r‐GO on MBE‐Grown Highly Resistive GaN

Prakash

Kumar

Singh

et al. 2019

Advanced Optical Materials

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materials to form heterostructures due to the improved functionality of electronic and optoelectronic devices. [1][2][3][4][5][6] The 2D material-based devices can have a revolutionizing impact on technology covering from vacuum photodetection and photovoltaics to optical modulators and high speed data communication. [7][8][9][10][11][12][13][14][15][16] Predominantly through vertical transport of photogenerated carriers, the hybrid structures allow us to overcome the inherent persistent photoconductivity (PPC), where photocurrent of the host material generally persists for a long duration even after the illumination is removed, generally observed in the compound III-nitride semiconductor materials. [17][18][19][20][21] Usually PPC occurs due to the presence of donor and acceptor states closer to the conduction band minimum (CBM) and valence band maximum (VBM), which provides a large number of electron and hole trap states in the host material, respectively. Alternatively, with an introduction of intrinsic semiconductor materials, the PPC could be reduced as the donor and acceptor states show a shift from the CBM and VBM edges toward the midgap positions, which facilitate fast recombination time in comparison to the transit time of photo generated carriers through host materials. This has resulted in high speed operation in photoconductive mode. [22] In particular, GaN integrated with reduced-graphene oxide (r-GO) is a promising heterostructure for achieving improved device characteristics such as low dark current, high spectral responsivity, and high response speed. [17] 2D r-GO makes an optically active heterojunction with GaN. The emphasis so far has been given on r-GO/GaN heterostructure operating in the photovoltaic mode where the photogenerated carriers are swiftly swept across the depletion region predominantly via vertical transport. However, in the photoconductive mode operation, where the photogenerated carriers traverse across the host materials under the influence of an external bias exceeding the built-in-field of the heterostructure device, suffers either from high leakage current and/or PPC due to inherently negatively charged defects rich GaN. [23] The intentional/unintentional doping of suitable species can cause compensation of free New generation of hybrid photodetectors may provide the optimal solution for compact, highly sensitive, durable, and reliable broadband ultraviolet (BUV) sensors. A high-performance dual-mode BUV photodetector based on melding of highly resistive GaN and reduced graphene oxide is reported. Under zero bias, the device exhibits a sub-picoampere dark current, high light-to-dark current (I Light /I Dark ) ratio of ≈3.8 × 10 3 and high BUV-visible rejection ratio (≈1.8 × 10 2 ) with fast rise and fall times. The photodetector displays remarkable stability when subject to extreme operating conditions. The photoresponse of the detector shows a dark current of ≈2.41 nA at ± 200 V bias, I Light /I Dark ratio of ≈200 and high BUV-vis rejection ratio (≈7 × 10 2 ). The response ...

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Properties of C‐doped GaN

Cited by 37 publications

References 48 publications

Two charge states of the CN acceptor in GaN: Evidence from photoluminescence

Two charge states of the CN acceptor in GaN: Evidence from photoluminescence

Determination of the concentration of impurities in GaN from photoluminescence and secondary-ion mass spectrometry

Long‐Term, High‐Voltage, and High‐Temperature Stable Dual‐Mode, Low Dark Current Broadband Ultraviolet Photodetector Based on Solution‐Cast r‐GO on MBE‐Grown Highly Resistive GaN

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