Polarity conversion of GaN nanowires grown by plasma-assisted molecular beam epitaxy

Concordel, Alexandre; Jacopin, Gwenolé; Gayral, B.; Garro, N.; Cros, A.; Daudin, B.

doi:10.1063/1.5094627

Cited by 9 publications

(11 citation statements)

References 41 publications

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“…The results are also consistent with studies showing polarity inversion induced by a variety of impurities and dopants, including Si (for GaN on Si and AlN), Mg (for GaN on GaN, SiC, Al 2 O 3 ), O (for AlN on AlN), O (for GaN on GaN), Al x O y (for GaN on GaN), Al (for GaN on Al 2 O 3 ), and Ti (for GaN on Al 2 O 3 ) …”

Section: Resultssupporting

confidence: 90%

“…The results are also consistent with studies showing polarity inversion induced by a variety of impurities and dopants, including Si (for GaN on Si and AlN), [31][32][33]44] Mg (for GaN on GaN, SiC, Al 2 O 3 ), [38][39][40]43,[45][46][47] O (for AlN on AlN), [48][49][50][51] O (for GaN on GaN), [52] Al x O y (for GaN on GaN), [52][53][54] Al (for GaN on Al 2 O 3 ), [55][56][57] and Ti (for GaN on Al 2 O 3 ). [58] The ability to induce polarity inversion may be useful for applications.…”

Section: Sample Al90:n10supporting

confidence: 88%

“…Thus, the ability to induce polarity inversion would be useful for obtaining metal‐polar films and nanowires. This may be especially important for nanowires, which are advantageous due to their lower defect densities, as spontaneously grown NWs are typically N‐polar, and because selective area nanowire growth on Si is facilitated by N‐polarity . In fact controlled polarity inversion has already been demonstrated both for epitaxial AlN layers and for spontaneously nucleated GaN nanowires using an oxidized interlayer.…”

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Eutectic Formation, V/III Ratio, and Controlled Polarity Inversion in Nitrides on Silicon

Roshko

Brubaker

Blanchard

et al. 2019

Physica Status Solidi (b)

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The crystallographic polarity of AlN grown on Si(111) by plasma‐assisted molecular beam epitaxy is intentionally inverted from N‐polar to Al‐polar at a planar boundary. The position of the inversion boundary is controlled by a two‐step growth process that abruptly changes from Al‐rich to N‐rich growth conditions. The polarity inversion is induced by the presence of Si, which is incorporated from an Al–Si eutectic layer that forms during the initial stages of AlN growth and floats on the AlN surface under Al‐rich growth conditions. When the growth conditions change to N‐rich, the Al and Si in the eutectic react with the additional N‐flux and are incorporated into the solid AlN film. Relatively low levels of Al–Si eutectic formation combined with lateral variations in the Si incorporation lead to nonuniformity in the polarity inversion and formation of surprisingly narrow, vertical inversion domains. The results suggest that intentional incorporation of uniform layers of Si may provide a method for producing polarity engineered nitride structures.

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Section: Resultssupporting

confidence: 90%

Section: Sample Al90:n10supporting

confidence: 88%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Eutectic Formation, V/III Ratio, and Controlled Polarity Inversion in Nitrides on Silicon

Roshko

Brubaker

Blanchard

et al. 2019

Physica Status Solidi (b)

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“…[96] Aiming at this problem, Concordel et al also achieved a Ga-polar GaN by inserting a thin layer of Ga x O y N z . [97] Therefore, the metal polarity of III-nitride NWs on various substrates can be realized, which plays an important role in optoelectronic field. In addition, different polarities of III-nitride NWs can also be achieved by adjusting growth conditions via MOCVD or metal-organic vapor phase epitaxy (MOVPE) technology.…”

Section: (6 Of 20)mentioning

confidence: 99%

Modulating Surface/Interface Structure of Emerging InGaN Nanowires for Efficient Photoelectrochemical Water Splitting

Lin

Wang

2020

Adv Funct Materials

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Photoelectrochemical (PEC) water splitting provides a promising approach to convert solar energy into hydrogen. Developing active, stable, and cost-effective semiconductors photoelectrodes is of great significance for achieving high-efficiency and large-scale hydrogen production. InGaN nanowires as an important candidate have gained a great upsurge in solar water splitting due to its tunable gap, high electron mobility, large active area, and excellent chemical stability. To obtain state-of-the-art InGaN nanowires-based photoelectrodes, tremendous efforts have been devoted to enhance light absorption capacity, charge carrier dynamics, and redox activity. In this review, recent advances in InGaN nanowires as photoelectrodes for PEC water splitting are comprehensively presented, with a focus on photoelectrode optimization strategies from the aspects of surface and interface structure modulation including doping engineering, energy band engineering, heterostructure engineering, and micro-nano engineering. The representative applications of InGaN nanowires-based PEC tandem cell are also discussed. Finally, perspectives on remaining challenges and future development are outlined.

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“…There is no consensus, however, about NW polarity. Although the majority of self-assembled GaN NWs grown on Si substrates are found to be N-polar, the coexistence of NWs with different polarities inside the NW ensemble has been observed [9,11,[19][20][21][22]. The formation of mixed-polarity NWs is not fully understood and the parameters influencing this behavior, which include the interface chemistry and the growth procedure, are still under debate.…”

Section: Introductionmentioning

confidence: 99%

Influence of Si Substrate Preparation Procedure on Polarity of Self-Assembled GaN Nanowires on Si(111): Kelvin Probe Force Microscopy Studies

et al. 2020

Self Cite

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The growth of GaN nanowires having a polar, wurtzite structure on nonpolar Si substrates raises the issue of GaN nanowire polarity. Depending on the growth procedure, coexistence of nanowires with different polarities inside one ensemble has been reported. Since polarity affects the optical and electronic properties of nanowires, reliable methods for its control are needed. In this work, we use Kelvin probe force microscopy to assess the polarity of GaN nanowires grown by plasma-assisted Molecular Beam Epitaxy on Si(111) substrates. We show that uniformity of the polarity of GaN nanowires critically depends on substrate processing prior to the growth. Nearly 18% of nanowires with reversed polarity (i.e., Ga-polar) were found on the HF-etched substrates with hydrogen surface passivation. Alternative Si substrate treatment steps (RCA etching, Ga-triggered deoxidation) were tested. However, the best results, i.e., purely N-polar ensemble of nanowires, were obtained on Si wafers thermally deoxidized in the growth chamber at ~1000 °C. Interestingly, no mixed polarity was found for GaN nanowires grown under similar conditions on Si(111) substrates with a thin AlOy buffer layer. Our results show that reversal of nanowires’ polarity can be prevented by growing them on a chemically uniform substrate surface, in our case on clean, in situ formed SiNx or ex situ deposited AlOy buffers.

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Polarity conversion of GaN nanowires grown by plasma-assisted molecular beam epitaxy

Cited by 9 publications

References 41 publications

Eutectic Formation, V/III Ratio, and Controlled Polarity Inversion in Nitrides on Silicon

Eutectic Formation, V/III Ratio, and Controlled Polarity Inversion in Nitrides on Silicon

Modulating Surface/Interface Structure of Emerging InGaN Nanowires for Efficient Photoelectrochemical Water Splitting

Influence of Si Substrate Preparation Procedure on Polarity of Self-Assembled GaN Nanowires on Si(111): Kelvin Probe Force Microscopy Studies

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