Controlled synthesis of nonpolar GaInN/GaN multiple-quantum-shells on GaN nanowires by metal-organic chemical vapour deposition

Lu, Weifang; Goto, Nanami; Murakami, Hedeki; Sone, Naoki; Iida, K.; Terazawa, Mizuki; Han, Dong‐Pyo; Iwaya, Motoaki; Tekeuchi, Tetsuya; Kamiyama, Satoshi; Akasaki, Isamu

doi:10.1016/j.apsusc.2020.145271

Cited by 18 publications

(23 citation statements)

References 35 publications

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“…Here, In-flakes are absent in the SEM characterizations of sample e, which was also confirmed in the other two samples grown at 750 °C and 710 °C. This consolidates that increasing the growth temperature of the GaN barriers can compensate the degradation of the MQS crystalline quality (morphology) at low growth temperatures of the GaInN wells [ 34 ]. Such an improvement is attributable to the unintentionally induced thermal annealing process of the GaInN wells during barrier growth.…”

Section: Resultsmentioning

confidence: 76%

“…Figure 5 (a i –c i ,a ii –c ii ) shows the planar and tilted-view of SEM images of patterns p 1 , p 2 , and p 3 of NW sample e, fabricated at a well growth temperature of 730 °C. With a high barrier growth temperature, uniform NWs were simultaneously achieved on patterns p 1 , p 2 , and p 3 of sample e. With standard growth sequence, the formation of In-flakes usually occurs as the MQS growth temperature decreases [ 34 ]. Here, In-flakes are absent in the SEM characterizations of sample e, which was also confirmed in the other two samples grown at 750 °C and 710 °C.…”

Section: Resultsmentioning

confidence: 99%

“…The height of the NWs was controlled via varying the growth time (55-65 s). Referring to the typical growth conditions on single-patterned templates [34], the growth temperature of the n-core was maintained at 1140 • C. During the n-core growth, the Ga and N were sourced from trimethylgallium (TMG) and NH 3 precursors, respectively, at a fixed V/III ratio of 20. The silane (SiH 4 ) doping precursor was injected at a rate of 2.79 × 10 −3 µmol/min) with H 2 carrier gas.…”

Section: Experimental Growthmentioning

confidence: 99%

“…However, the diameter was only enlarged at the top part of the NWs, and many flakes were formed at the junction between the semi-polar and non-polar planes, as shown in Figure 3(d i -d iii ). Typically, the impinged precursors on the top area of the NWs mainly contribute to the growth at the top area [34,36]. The flakes may have been formed by the high growth rate at the apex and the overflow of precursors under the higher TEG flow rate, which can reduce the diffusion of impinged adatoms toward the bottom area.…”

Section: Effect Of Teg Flow Rate On Emission Wavelengthmentioning

confidence: 99%

“…Samples d, e, and f were fabricated with well growth temperature of 750 • C, 730 • C, and 710 • C, respectively, and the effect of the well growth temperature on the emission wavelength was investigated. Figure 5(a i -c i ,a ii -c ii ) shows the planar and tilted-view of SEM images of patterns p 1 , p 2 , and p 3 of NW sample e, fabricated at a well growth temperature of 730 • C. With a high barrier growth temperature, uniform NWs were simultaneously achieved on patterns p 1 , p 2 , and p 3 of sample e. With standard growth sequence, the formation of In-flakes usually occurs as the MQS growth temperature decreases [34]. Here, In-flakes are absent in the SEM characterizations of sample e, which was also confirmed in the other two samples grown at 750 • C and 710 • C. This consolidates that increasing the growth temperature of the GaN barriers can compensate the degradation of the MQS crystalline quality (morphology) at low growth temperatures of the GaInN wells [34].…”

Section: Enhancing Emission Wavelength By Lowering the Growth Temperamentioning

confidence: 99%

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Development of Monolithically Grown Coaxial GaInN/GaN Multiple Quantum Shell Nanowires by MOCVD

Ito

Sone

et al. 2020

Nanomaterials

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Broadened emission was demonstrated in coaxial GaInN/GaN multiple quantum shell (MQS) nanowires that were monolithically grown by metalorganic chemical vapor deposition. The non-polar GaInN/GaN structures were coaxially grown on n-core nanowires with combinations of three different diameters and pitches. To broaden the emission band in these three nanowire patterns, we varied the triethylgallium (TEG) flow rate and the growth temperature of the quantum barriers and wells, and investigated their effects on the In incorporation rate during MQS growth. At higher TEG flow rates, the growth rate of MQS and the In incorporation rate were promoted, resulting in slightly higher cathodoluminescence (CL) intensity. An enhancement up to 2–3 times of CL intensity was observed by escalating the growth temperature of the quantum barriers to 800 °C. Furthermore, decreasing the growth temperature of the quantum wells redshifted the peak wavelength without reducing the MQS quality. Under the modified growth sequence, monolithically grown nanowires with a broaden emission was achieved. Moreover, it verified that reducing the filling factor (pitch) can further promote the In incorporation probability on the nanowires. Compared with the conventional film-based quantum well LEDs, the demonstrated monolithic coaxial GaInN/GaN nanowires are promising candidates for phosphor-free white and micro light-emitting diodes (LEDs).

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Section: Resultsmentioning

confidence: 76%

Section: Resultsmentioning

confidence: 99%

Section: Experimental Growthmentioning

confidence: 99%

Section: Effect Of Teg Flow Rate On Emission Wavelengthmentioning

confidence: 99%

Section: Enhancing Emission Wavelength By Lowering the Growth Temperamentioning

confidence: 99%

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Development of Monolithically Grown Coaxial GaInN/GaN Multiple Quantum Shell Nanowires by MOCVD

Ito

Sone

et al. 2020

Nanomaterials

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Growth Defects in InGaN‐Based Multiple‐Quantum‐Shell Nanowires with Si‐Doped GaN Cap Layers and Tunnel Junctions

Okuno

Mizutani

Iida

et al. 2022

Physica Status Solidi (b)

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Herein, the growth mechanism and defect structure of GaN‐based nanowire multiple‐quantum‐shells (NW‐MQSs) with cap layers combining tunnel junctions and n‐GaN are investigated in detail. In the NW‐MQS structure, defect structures are formed in three regions: (i) From the c‐plane active layer at the tip of NW because of the low crystal quality of the active layer. (ii) Basal‐plane stacking faults (BSFs) with partial dislocations (PDs) are generated from the m‐planes of the NW‐MQSs; these defects are triggered by the silicon nitride (SiNx) formed on the NW surface. While some defects terminate because of the half loop formed by the PDs along the lateral growth of cap layers, others terminate at the coalesced region of the cap layers grown from adjacent MQSs. (iii) Line defects due to low‐angle grain boundaries and planar defects due to the BSFs in region (ii) are formed in the region wherein cap layers coalesce. The defects reaching the surface of the cap layers predominantly depend on the number of defects generated from the c‐plane active layers in region (i). The growth mode and propagation mechanism of such defects are associated, and a method for realizing optical devices based on the high‐quality NW‐MQS structures is discussed.

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Optimization of In‐Reactor In Situ Activation Annealing Conditions for Tunnel Junction Layers in Multiquantum Shell GaN‐Based Devices

Takahashi,

Yamanaka,

et al. 2024

Physica Status Solidi (b)

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For realizing room‐temperature continuous‐wave operation in core–shell GaN nanowire‐based semiconductor lasers, certain device characteristics are required, namely, a low threshold current and low operating voltage. To reduce the operating voltage and inject current into the m‐plane multiquantum shell (MQS) active region, a new structure with a tunnel junction and embedded n‐GaN is proposed. One of the problems in this proposed device architecture is the high resistance at the tunnel junction layer due to hydrogen passivation in the insufficiently activated p‐GaN shell. In situ activation annealing and suppression of re‐passivation during subsequent growth are necessary to reduce the operating voltage. Herein, the time and temperature dependence of in situ activation annealing in a reactor to lower the resistance of tunnel junction layers grown on nanowires with nonpolar m‐planes is investigated. Subsequent n+‐GaN growth is implemented at 550 °C. As a result, the turn‐on voltage is observed to be dependent on the activation annealing time and temperature. The lowest turn‐on voltage is ≈5.4 V at an activation annealing time of 30 min and activation annealing temperature of 800 °C.

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Controlled synthesis of nonpolar GaInN/GaN multiple-quantum-shells on GaN nanowires by metal-organic chemical vapour deposition

Cited by 18 publications

References 35 publications

Development of Monolithically Grown Coaxial GaInN/GaN Multiple Quantum Shell Nanowires by MOCVD

Development of Monolithically Grown Coaxial GaInN/GaN Multiple Quantum Shell Nanowires by MOCVD

Growth Defects in InGaN‐Based Multiple‐Quantum‐Shell Nanowires with Si‐Doped GaN Cap Layers and Tunnel Junctions

Optimization of In‐Reactor In Situ Activation Annealing Conditions for Tunnel Junction Layers in Multiquantum Shell GaN‐Based Devices

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