Slow decay of a defect‐related emission band at 2.05 eV in AlN: Signatures of oxygen‐related DX states

Lamprecht, Matthias; Grund, Christiane; Bauer, Sebastian; Collazo, Ramón; Sitar, Zlatko; Thonke, Klaus

doi:10.1002/pssb.201600338

Cited by 11 publications

(31 citation statements)

References 62 publications

(113 reference statements)

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“…Based on these results, we identify a common excitation channel for all bands at around 3.95 eV (#b), and two additional ones at around 3.6 eV (#a) and around 4.3 eV (#c) for the other two samples. The common excitation channel at 3.95 eV was already tentatively assigned by Lamprecht et al to an electron excitation from a deep carbon related acceptor or

V_{Al}

into the conduction band, based on studies on sample #S1 and on another sample equivalent to sample #S3 used here.…”

Section: Resultsmentioning

confidence: 64%

“…), the TRPL measurements of the 1.86 eV PL band in sample #S2 show two distinct characteristic lifetimes at 30 K (data not shown here): a slower part with

τ_{1} \approx false(3.2 \pm 0.3 false)

ms and a faster part with a lifetime shorter than the time resolution of the setup used. Again, this similarity in TRPL hints to equivalent underlying recombination processes of the 1.86 eV band and the 2.05 eV band, that is, spectrally overlapping contributions of energetically close lying initial

D^{0}

and

{DX}^{-}

states in a transition to a deep acceptor .…”

Section: Resultsmentioning

confidence: 67%

“…This deep acceptor was tentatively assigned to carbon, an

V_{Al}

or a related complex. In temperature dependent PL measurements below room temperature, Lamprecht et al found also an additional activation energy of around 20–30 meV for the 2.05 eV PL band and a deactivation of component #5 in the same temperature range.…”

Section: Resultsmentioning

confidence: 93%

“…Obviously, in both samples, the same competition of recombination paths exists. The change in relative intensity of these two dominant bands in sample #S1 and #S2 is presumably caused by different concentrations of shallow donors or deep acceptors involved in the donor–acceptor‐type pair transitions due to different growth conditions. For temperature variation between 15 and 160 K, we find a more or less constant signal for the 2.05 eV (#4) band, but a decrease of the lower 1.86 eV (#3) band starting at

T > 70

K, hinting to a shallower initial state of the latter emission.…”

Section: Resultsmentioning

confidence: 99%

“…The assignments of these defect‐related bands are partially unclear or contradicting, and further clarification is needed. Lamprecht et al discussed the photoluminescence (PL) bands originating from transitions from Si and O DX‐centers to deep acceptors in AlN . Here, we studied for two adjacent lower energy bands centered at 1.68 and 1.86 eV the temperature dependence of the PL intensity and PL lifetime.…”

Section: Introductionmentioning

confidence: 95%

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Model for the deep defect‐related emission bands between 1.4 and 2.4 eV in AlN

Lamprecht

Jmerik

Collazo

et al. 2017

Physica Status Solidi (b)

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We report on defect‐related photoluminescence bands in the range from 1.4 to 2.4 eV in aluminum nitride bulk crystals and layers. Using continuous photoluminescence, photoluminescence excitation, and time‐resolved photoluminescence spectroscopy, we assign these bands to donor–acceptor pair transitions between shallow donor states or related slightly deeper DX− states of silicon or oxygen donors, and three different types of deep acceptors. These three different acceptors are most likely a (VAl−2false(ON)) complex, a (VAl−ON) complex, and an aluminum vacancy VAl, or different charge states of these.

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V_{Al}

into the conduction band, based on studies on sample #S1 and on another sample equivalent to sample #S3 used here.…”

Section: Resultsmentioning

confidence: 64%

“…), the TRPL measurements of the 1.86 eV PL band in sample #S2 show two distinct characteristic lifetimes at 30 K (data not shown here): a slower part with

τ_{1} \approx false(3.2 \pm 0.3 false)

D^{0}

and

{DX}^{-}

states in a transition to a deep acceptor .…”

Section: Resultsmentioning

confidence: 67%

“…This deep acceptor was tentatively assigned to carbon, an

V_{Al}

Section: Resultsmentioning

confidence: 93%

T > 70

K, hinting to a shallower initial state of the latter emission.…”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 95%

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Model for the deep defect‐related emission bands between 1.4 and 2.4 eV in AlN

Lamprecht

Jmerik

Collazo

et al. 2017

Physica Status Solidi (b)

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Optical signatures of silicon and oxygen related DX centers in AlN

Thonke

Lamprecht

Collazo

et al. 2017

Phys. Status Solidi A

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Bulk AlN crystals typically contain high concentrations of oxygen, silicon, and carbon À as also state-of-the art epitaxial layers typically do, depending on the specific growth conditions. In optical spectroscopy, such crystals show broad bands in the region from 2-5 eV in absorption and emission. We investigated several emission bands in the range from 1.4 to 1.9 eV, especially those centred at 2.0 and 2.4 eV, which under below-bandgap excitation with a 325 nm laser dominate the photoluminescence (PL) spectra both at low and at room temperature. We find clear indications that all these transitions occur between different states of the shallow donors Si or O, and deep acceptors. The donors undergo lattice relaxation and form DX centres. Depending on temperature, the initial state is either a long-lived (S ¼ 1) DXcentre state of the donors, a shallow EMT-like conventional donor state, or a free electron À with markedly different relaxation times for the optical transitions under below-bandgap excitation. The acceptor involved in these PL bands is likely linked to aluminum vacancies. Based on our data, we develop configuration coordinate diagrams and a combined level scheme for multiple transitions in the range from 1.4 to 2.4 eV.Tentative level scheme for PL bands observed in AlN in the range from 1.4 to 2.4 eV.

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A Combination of Ion Implantation and High‐Temperature Annealing: Donor–Acceptor Pairs in Carbon‐Implanted AlN

Peters

Spende

Wolter

et al. 2023

Physica Status Solidi (a)

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Herein, carbon‐implanted high‐temperature annealed (HTA) AlN layers are analyzed and donor–acceptor pair (DAP) transitions probably between the two most abundant impurities, carbon and oxygen, are identified. Both are regarded as the main, hard‐to‐avoid impurities in crystal growth. Oxygen is believed to lead to absorption in the deep UV below a wavelength of 250 nm. In contrast, carbon is the most likely candidate to be responsible for a distinct absorption band around 265 nm. This interpretation has recently been challenged. In this study, carbon‐implanted and HTA AlN layers with ion fluences above 8.1 × 1015 cm−2 are analyzed using low‐temperature and time‐resolved cathodoluminescence spectroscopy. Due to the high concentration of oxygen inside the AlN, as a result of the HTA process, a DAP transition between a most likely carbon‐related acceptor and ON is observed. The measured temperature‐ and power‐dependent blueshift of the peak emission energy as well as the luminescence transients can be clearly explained by a continuous change from a DAP transition at low temperature to a free electron to acceptor transition with increasing temperature. The findings are supported by a configurational coordinate model that describes the measured behavior qualitatively.

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Slow decay of a defect‐related emission band at 2.05 eV in AlN: Signatures of oxygen‐related DX states

Cited by 11 publications

References 62 publications

Model for the deep defect‐related emission bands between 1.4 and 2.4 eV in AlN

Model for the deep defect‐related emission bands between 1.4 and 2.4 eV in AlN

Optical signatures of silicon and oxygen related DX centers in AlN

A Combination of Ion Implantation and High‐Temperature Annealing: Donor–Acceptor Pairs in Carbon‐Implanted AlN

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