Properties of the yellow luminescence in undoped GaN epitaxial layers

Hofmann, D. M.; Kovalev, D.; Steude, G.; Meyer, B. K.; Hoffmann, A.; Eckey, L.; Heitz, R.; Detchprom, T; Amano, Hiroshi; Akasaki, Isamu

doi:10.1103/physrevb.52.16702

Cited by 253 publications

(192 citation statements)

References 14 publications

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“…The yellow emission has a maximum at 2.3 eV and a FWHM of 500 meV and is described by an activation energy of 20 AE 2 meV. These values are in agreement with previously reported values [4] assuming a recombination model where a shallow donor and a deep donor are involved.…”

Section: Resultssupporting

confidence: 81%

Low Temperature Photoluminescence, Transient Photoconductivity and Microwave Reflection for Optical Properties and Transport in PLD‐GaN

Niehus¹,

Sanguino²,

Schwarz³

et al. 2002

phys. stat. sol. (c)

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Optical and transport data on GaN samples grown by low-temperature pulsed laser deposition are presented. Large below-gap band tails are observed in optical absorption spectroscopy. The most intense photoluminescence lines of medium crystalline quality samples can be attributed to excitons bounded to stacking faults. The samples of the highest quality show, besides the ubiquitous yellow band, a large near band emission (NBE) peaking at 3.47 eV. The large width of the NBE is attributed to the joint effects of the band tails and an elevated carrier concentration. Secondary photocurrent transients show a slow decay reaching the millisecond time region for a variety of excitation wavelengths and intensities, with a power law decay exponent of around --0.3. The long times are attributed to the trapping of excess carriers in extended band tail states. From the comparison of photocurrent decay with excess carrier-induced microwave reflection it is concluded that the decay dynamics at the air/film and film/substrate interfaces are identical.Introduction GaN is one of the base materials for modern electronic and optoelectronic devices such as light emitting diodes (LEDs), solar blind UV detectors, laser diodes (LDs) or high-mobility electron transistors (HEMTs) [1]. Despite impressive technical advances, some basic materials issues remain to be resolved. One of these is the elevated density of unwanted impurities that appear in the material independently of the deposition technique. The metalorganic chemical vapour deposition (MOCVD) technique, for instance, relies always on a precursor gas that may introduce unwanted effects.We presented recently a new approach for depositing GaN films, a hybrid, two-step, low-temperature pulsed laser deposition (PLD) [2]. In this work we study the optical properties and transport in gallium nitride (GaN) deposited by this technique. Optical spectroscopy (transmission and photoluminescence measurements) and photoconductivity data are presented.

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Section: Resultssupporting

confidence: 81%

Low Temperature Photoluminescence, Transient Photoconductivity and Microwave Reflection for Optical Properties and Transport in PLD‐GaN

Niehus¹,

Sanguino²,

Schwarz³

et al. 2002

phys. stat. sol. (c)

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“…Glaser et al and Hofmann et al reported measurements on optically detected magnetic resonance that indicated the YL transition involved a deep donor, with carbon suggested to be a shallow acceptor. 5,6 The deep donor in these studies was speculated to be a deep double donor due to nitrogen vacancies, though no deep donor level has been verified to date. Similarly, Fischer et al attributed an acceptor site of 230 meV depth to carbon impurities based on thermal quenching experiments on near band edge PL peaks.…”

Section: Introductionmentioning

confidence: 99%

Carbon doping of GaN with CBr4 in radio-frequency plasma-assisted molecular beam epitaxy

Green

Mishra

Speck

2004

Journal of Applied Physics

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Carbon tetrabromide (CBr 4 ) was studied as an intentional dopant during rf plasma molecular beam epitaxy of GaN. Secondary ion mass spectroscopy was used to quantify incorporation behavior. Carbon was found to readily incorporate under Ga-rich and N-rich growth conditions with no detectable bromine incorporation. The carbon incorporation ͓C͔ was found to be linearly related to the incident CBr 4 flux. Reflection high-energy electron diffraction, atomic force microscopy and x-ray diffraction were used to characterize the structural quality of the film's postgrowth. No deterioration of structural quality was observed for ͓C͔ from mid 10 17 to ϳ10 19 cm Ϫ3 . The growth rate was also unaffected by carbon doping with CBr 4 . The electrical and optical behavior of carbon doping was studied by co-doping carbon with silicon. Carbon was found to compensate the silicon although an exact compensation factor was difficult to extract from the data. Photoluminescence was performed to examine the optical performance of the films. Carbon doping was seen to monotonically decrease the band edge emission. Properties of carbon-doped GaN are interpreted to be consistent with recent theoretical work describing incorporation of carbon as function of Fermi level conditions during growth.

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“…11 One characteristic of GaN observed in photoluminescence ͑PL͒ spectra is yellow luminescence ͑YL͒. [12][13][14][15] Kim et al reported multiphotoninduced PL in the YL band and found that the multiphoton PL excitation ͑PLE͒ spectrum exhibits resonance that is attributable to the mid-gap defect states. 6 Sun et al obtained a large two-photon absorption ͑TPA͒ coefficient below the band gap and demonstrated two-photon-induced YL imaging.…”

mentioning

confidence: 99%

Two-photon absorption and multiphoton-induced photoluminescence of bulk GaN excited below the middle of the band gap

Toda

Matsubara

Morita

et al. 2003

Applied Physics Letters

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Optical nonlinearity in the yellow luminescence (YL) band of GaN was investigated using thick bulk samples. Transient pump–probe measurements revealed strong transmission changes due to two-photon absorption(TPA) even at the middle of the YL band. The TPA coefficient evaluated reaches ∼5 cm/GW∼5 cm/GW at about 1.3 eV, which was as large as the mid-gap resonance. The TPA spectrum clearly showed that the observed large nonlinearity originated from the YL band. On the basis of efficient TPA in the YL band, relaxation processes in the multiphoton-induced photoluminescence excitation spectrum were also investigated

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Properties of the yellow luminescence in undoped GaN epitaxial layers

Cited by 253 publications

References 14 publications

Low Temperature Photoluminescence, Transient Photoconductivity and Microwave Reflection for Optical Properties and Transport in PLD‐GaN

Low Temperature Photoluminescence, Transient Photoconductivity and Microwave Reflection for Optical Properties and Transport in PLD‐GaN

Carbon doping of GaN with CBr4 in radio-frequency plasma-assisted molecular beam epitaxy

Two-photon absorption and multiphoton-induced photoluminescence of bulk GaN excited below the middle of the band gap

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