Polarized photoluminescence excitation spectroscopy of a-plane InGaN/GaN multiple quantum wells grown on r-plane sapphire

Kundys, Dmytro; Schulz, Stefan; Oehler, Fabrice; Sutherland, Danny; Badcock, T. J.; Dawson, Philip E.; Kappers, Menno J.; Oliver, Rachel A.; Humphreys, C. J.

doi:10.1063/1.4868692

Cited by 11 publications

(10 citation statements)

References 20 publications

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“…Each spectrum exhibits a distinct low energy emission tail that appears relatively stronger in the samples with low indium incorporation. Emission on the low energy side of the main spectrum has been reported in non‐polar InGaN/GaN QW structures grown on sapphire and has been attributed to BSF‐associated emission . As the BSF densities in these samples are very small we do not believe that the low energy tail can be attributed to this recombination path.…”

Section: Resultsmentioning

confidence: 84%

Optical studies of non‐polar m‐plane () InGaN/GaN multi‐quantum wells grown on freestanding bulk GaN

Sutherland

Zhu

Griffiths

et al. 2015

Physica Status Solidi (b)

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We report on the optical properties of non-polar m-plane InGaN/GaN multi-quantum wells (MQWs) grown on ammonothermal bulk GaN substrates. The low temperature continuous wave (CW) photoluminescence spectra are broad with a characteristic low energy tail. The majority of the emission bands decay with a time constant~300 ps, but detailed photoluminescence time decay and time resolved spectroscopy measurements revealed the existence of a distinct slowly decaying emission band. This slowly decaying component is responsible for the low energy tails observed in the CW spectra. Scanning electron microscopy-cathodoluminescence (SEM-CL) studies show that the low energy emission band originates from regions across step-bunches, which are associated to the GaN substrate miscut. Subsequent scanning transmission electron microscopy imaging demonstrates that semi-polar QWs had formed continuous layers on the step bunches between the m-plane QWs and were responsible for the slower decaying, low energy emission band. Thus we assign the asymmetric low energy emission tails observed in photoluminescence studies to the formation of semi-polar facet QWs across the step bunches associated with the GaN miscut.

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Section: Resultsmentioning

confidence: 84%

Optical studies of non‐polar m‐plane () InGaN/GaN multi‐quantum wells grown on freestanding bulk GaN

Sutherland

Zhu

Griffiths

et al. 2015

Physica Status Solidi (b)

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“…The reason for the slow photo response of the device is the high threading dislocations and basal stacking faults. 29 For comparing the performance of the device, similar photodetector structure was fabricated on bare a-GaN epilayer. The device showed no response to IR radiation but it showed UV sensitivity.…”

Section: Resultsmentioning

confidence: 99%

High indium non-polar InGaN clusters with infrared sensitivity grown by PAMBE

et al. 2015

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Studies on the optical properties of InGaN alloy of relatively higher indium content are of potential interest to understand the effect of indium content on the optical band gap of epitaxial InGaN. We report the growth of self assembled non-polar high indium clusters of In0.55Ga0.45N over non-polar (11-20) a-plane In0.17Ga0.83N epilayer grown on a-plane (11-20)GaN/(1-102) r-plane sapphire substrate using plasma assisted molecular beam epitaxy (PAMBE). Such structures are potential candidates for high brightness LEDs emitting in longer wavelengths. The high resolution X-ray diffraction studies revealed the formation of two distinct compositions of InxGa1−xN alloys, which were further confirmed by photoluminescence studies. A possible mechanism for the formation of such structure was postulated which was supported with the results obtained by energy dispersive X-ray analysis. The structure hence grown when investigated for photo-detecting properties, showed sensitivity to both infrared and ultraviolet radiations due to the different composition of InGaN region.

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“…The polarisation dependent excitation spectroscopy reveals exciton transitions associated with the different valence sub-bands; this not only enables measurement of the valence sub-band energy splitting as described previously [3,20–23] but can also be used to help to identify the nature of the recombination processes. For the time-resolved PL and PL decay time measurements, a frequency doubled mode-locked Ti:sapphire laser operating at a repetition rate of 800 kHz and emitting light with a photon energy of 3.18 eV was used as the excitation source and the signal processed with a time-correlated single photon counting system.…”

Section: Methodsmentioning

confidence: 99%

A study of the optical and polarisation properties of InGaN/GaN multiple quantum wells grown on a-plane and m-plane GaN substrates

Kundys

Sutherland

Davies

et al. 2016

Science and Technology of Advanced Materials

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We report on a comparative study of the low temperature emission and polarisation properties of InGaN/GaN quantum wells grown on nonpolar () a-plane and () m-plane free-standing bulk GaN substrates where the In content varied from 0.14 to 0.28 in the m-plane series and 0.08 to 0.21 for the a-plane series. The low temperature photoluminescence spectra from both sets of samples are broad with full width at half maximum height increasing from 81 to 330 meV as the In fraction increases. Photoluminescence excitation spectroscopy indicates that the recombination mainly involves strongly localised carriers. At 10 K the degree of linear polarisation of the a-plane samples is much smaller than of the m-plane counterparts and also varies across the spectrum. From polarisation-resolved photoluminescence excitation spectroscopy we measured the energy splitting between the lowest valence sub-bands to lie in the range of 23–54 meV for the a- and m-plane samples in which we could observe distinct exciton features. Thus the thermal occupation of a higher valence sub-band cannot be responsible for the reduction of the degree of linear polarisation at 10 K. Time-resolved spectroscopy indicates that in a-plane samples there is an extra emission component which is at least partly responsible for the reduction in the degree of linear polarisation.

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Polarized photoluminescence excitation spectroscopy of a-plane InGaN/GaN multiple quantum wells grown on r-plane sapphire

Cited by 11 publications

References 20 publications

Optical studies of non‐polar m‐plane () InGaN/GaN multi‐quantum wells grown on freestanding bulk GaN

Optical studies of non‐polar m‐plane () InGaN/GaN multi‐quantum wells grown on freestanding bulk GaN

High indium non-polar InGaN clusters with infrared sensitivity grown by PAMBE

A study of the optical and polarisation properties of InGaN/GaN multiple quantum wells grown on a-plane and m-plane GaN substrates

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