Shape transformation of nanoporous GaN by annealing: From buried cavities to nanomembranes

Yerino, Christopher D.; Zhang, Yu; Leung, Benjamin; Lee, Minjoo Larry; Hsu, Ta Cheng; Wang, Chun-Kai; Peng, Wei; Han, Jung

doi:10.1063/1.3601861

Cited by 44 publications

(20 citation statements)

References 15 publications

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“…Annealing was carried out at 1090°C for 10 min, and a thick InGaN layer was then regrown at 770°C. The transformation of the geometry of the NP GaN layers during the high-temperature annealing and regrowth has been reported previously [24,25]. NP GaN is metastable at high temperatures because of the large surface area; this results in the transformation of the geometry of the nanopores via surface atomic diffusion.…”

Section: Resultsmentioning

confidence: 92%

Optical study of phase-separated thick InGaN layers grown on a compliant substrate

et al. 2015

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The optical properties of thick InGaN layers grown on a compliant substrate (CS) were investigated. The CS was fabricated by thermal deformation of nanoporous GaN during high-temperature annealing. The strain sharing between the InGaN with CS was characterized using high-resolution X-ray diffraction, and we found a reduced in-plane strain of the InGaN on the CS. Photoluminescence (PL) spectra exhibited double peaks associated with discontinuous strain relaxation during the growth of the InGaN films. The strain sharing suppressed defect formation in the InGaN grown on CS, whereas the degree of indium fluctuation was similar because the phase separation resulted from spinodal decomposition. The temperature dependence of the PL spectra and internal quantum efficiency were analyzed as a function of the thickness of the InGaN layer. The effects of the CS on the growth of thick InGaN layers are discussed.

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Section: Resultsmentioning

confidence: 92%

Optical study of phase-separated thick InGaN layers grown on a compliant substrate

et al. 2015

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“…Among other methods of micromachining GaN, one can mention an effective technology for shaping GaN on both the nanoscale and microscale that was recently proposed [30]. This technology is suitable for obtaining buried cavities or semiconductor-on-air structures, including a monocrystalline GaN nanomembrane.…”

Section: Other Technological Methodsmentioning

confidence: 99%

“…The prepared NP GaN samples were loaded into a MOCVD reactor for annealing in a N 2 /NH 3 or H 2 /NH 3 ambient. It was suggested that the shape transformation of NP GaN takes place due to surface and gas phase diffusion driven by the minimization of total surface energy, as well as due to dissociation of GaN and the formation of Ga droplets [30]. A 200-nm-thick nanomembrane was prepared by annealing a GaN layer with a specially designed profile in porosity obtained by using a 2-step EC etching process.…”

Section: Other Technological Methodsmentioning

confidence: 99%

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GaN nanostructuring for the fabrication of thin membranes and emerging applications

Tiginyanu¹,

Ursaki²

2014

Turk J Phys

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Abstract:We present a review of technological methods developed in recent years for the purpose of gallium nitride nanostructuring, with the main focus on fabrication of thin GaN membranes. In particular, we report on traditional methods of wet etching undercutting for membrane manufacturing, technologies applied for the fabrication of photonic crystal structures based on GaN nanomembranes, double side processing, and surface charge lithography. Prospects of membrane applications in photonic devices, sensors, and microoptoelectromechanical and nanoelectromechanical systems are discussed, taking into account the advantageous piezoelectric, optical, and mechanical properties of GaN and related III-V nitride materials.

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“…9 Yerino et al, developed another technique which does not rely on a buried sacrificial layer, by using anodic electrochemical etching with a varying potential bias to form undersurface buried cavities. 10 Subsequent annealing in nitrogen/ammonia causes the cavities to merge together which allows the surface to get exfoliated. Here, we demonstrate a new technique for exfoliating GaN nanomembranes with novel characteristics, namely, the non-radiative cores of their threading dislocations (TDs) being etched away.…”

Section: Introductionmentioning

confidence: 99%

Chemical exfoliation and optical characterization of threading-dislocation-free gallium-nitride ultrathin nanomembranes

ElAfandy

Majid

et al. 2014

SPIE Proceedings

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Semiconductor nanostructures have generated tremendous scientific interests as well as practical applications stemming from the engineering of low dimensional physics phenomena. Unlike 0D and 1D nanostructures, such as quantum dots and nanowires, respectively, 2D structures, such as nanomembranes, are unrivalled in their scalability for high yield manufacture and are less challenging in handling with the current transfer techniques. Furthermore, due to their planar geometry, nanomembranes are compatible with the current complementary metal oxide semiconductor (CMOS) technology. Due to these superior characteristics, there are currently different techniques in exfoliating nanomembranes with different crystallinities, thicknesses and compositions. In this work we demonstrate a new facile technique of exfoliating gallium nitride (GaN) nanomembranes with novel features, namely with the non-radiative cores of their threading-dislocations (TDs) being etched away. The exfoliation process is based on engineering the gallium vacancy (V Ga ) density during the GaN epitaxial growth with subsequent preferential etching. Based on scanning and transmission electron microscopies, as well as micro-photoluminescence measurements, a model is proposed to uncover the physical processes underlying the formation of the nanomembranes. Raman measurements are also performed to reveal the internal strain within the nanomembranes. After transferring these freely suspended 25 nm thin GaN nanomembranes to other substrates, we demonstrate the temperature dependence of their bandgap by photoluminescence technique, in order to shed light on the internal carrier dynamics.

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Shape transformation of nanoporous GaN by annealing: From buried cavities to nanomembranes

Cited by 44 publications

References 15 publications

Optical study of phase-separated thick InGaN layers grown on a compliant substrate

Optical study of phase-separated thick InGaN layers grown on a compliant substrate

GaN nanostructuring for the fabrication of thin membranes and emerging applications

Chemical exfoliation and optical characterization of threading-dislocation-free gallium-nitride ultrathin nanomembranes

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