AlN/GaN double-barrier resonant tunneling diodes grown by metal-organic chemical vapor deposition

Bayram, Can; Vashaei, Z.; Razeghi, Manijeh

doi:10.1063/1.3294633

Cited by 92 publications

(54 citation statements)

References 22 publications

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“…3. The full-width half maximum of the GaN (0002) peak ( ¼ 0.06°) is in the similar range to that measured from GaN grown on sapphire or SiC [25][26][27] (see Supplementary Table 1). The phi scan was performed by rotating the sample around its surface normal (Fig.…”

Section: Resultssupporting

confidence: 60%

“…2e). Notably, this density is in the comparable range with that of AlN-buffer-assisted GaN films grown on the conventional substrates, sapphire or SiC by using MOCVD (5 Â 10 8 cm À 2 -8 Â 10 9 cm À 2 ) (refs [25][26][27]. Such low dislocation density could be obtained even with B23% mismatch between GaN and graphene and even without employing AlN buffers, thanks to the successful vdWE of GaN on graphene.…”

Section: Resultsmentioning

confidence: 53%

See 1 more Smart Citation

Principle of direct van der Waals epitaxy of single-crystalline films on epitaxial graphene

Kim¹,

Bayram²,

Park³

et al. 2014

Nat Commun

360

299

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There are numerous studies on the growth of planar films on sp 2 -bonded two-dimensional (2D) layered materials. However, it has been challenging to grow single-crystalline films on 2D materials due to the extremely low surface energy. Recently, buffer-assisted growth of crystalline films on 2D layered materials has been introduced, but the crystalline quality is not comparable with the films grown on sp 3 -bonded three-dimensional materials. Here we demonstrate direct van der Waals epitaxy of high-quality single-crystalline GaN films on epitaxial graphene with low defectivity and surface roughness comparable with that grown on conventional SiC or sapphire substrates. The GaN film is released and transferred onto arbitrary substrates. The post-released graphene/SiC substrate is reused for multiple growth and transfer cycles of GaN films. We demonstrate fully functional blue light-emitting diodes (LEDs) by growing LED stacks on reused graphene/SiC substrates followed by transfer onto plastic tapes.

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Section: Resultssupporting

confidence: 60%

Section: Resultsmentioning

confidence: 53%

Principle of direct van der Waals epitaxy of single-crystalline films on epitaxial graphene

Kim¹,

Bayram²,

Park³

et al. 2014

Nat Commun

360

299

View full text Add to dashboard Cite

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“…The existence of defects such as charge traps and screw dislocations has led to the need for systematic verification of the origin of negative differential resistance (NDR) features. [13][14][15][16][17] Another important characteristic of AlGaN/GaN heterostructures is the large built-in electrostatic fields due to both spontaneous and piezoelectric polarization which alter the current-voltage (I-V) characteristics significantly. Recent advances in growth technology have reduced threading dislocation densities substantially to allow repeatable measurement of wurtzite and cubic AlGaN RTDs [18][19][20][21][22][23] and sequential tunneling devices.…”

Section: Introductionmentioning

confidence: 99%

Coherent vertical electron transport and interface roughness effects in AlGaN/GaN intersubband devices

Grier

Valavanis

Edmunds

et al. 2015

Journal of Applied Physics

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We investigate electron transport in epitaxially grown nitride-based resonant tunneling diodes (RTDs) and superlattice sequential tunneling devices. A density-matrix model is developed, and shown to reproduce the experimentally measured features of the current-voltage curves, with its dephasing terms calculated from semi-classical scattering rates. Lifetime broadening effects are shown to have a significant influence in the experimental data. Additionally, it is shown that the interface roughness geometry has a large effect on current magnitude, peak-to-valley ratios and misalignment features; in some cases eliminating negative differential resistance entirely in RTDs. Sequential tunneling device characteristics are dominated by a parasitic current that is most likely to be caused by dislocations; however, excellent agreement between the simulated and experimentally measured tunneling current magnitude and alignment bias is demonstrated. This analysis of the effects of scattering lifetimes, contact doping and growth quality on electron transport highlights critical optimization parameters for the development of III-nitride unipolar electronic and optoelectronic devices. V C 2015 AIP Publishing LLC. [http://dx

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“…43,44 The huge strain in the structures considered in this study might render them unsuitable for actual applications, although there have been numerous attempts to make resonant-tunneling diodes using GaN leads that have even larger strains. [18][19][20]22,23 Using AlGaInN layers could be helpful but complicates growth. With this additional criterion, one could design structures that are both polarization and strain balanced.…”

Section: B Prospects and Challengesmentioning

confidence: 99%

“…Presently, current-driven devices are mostly limited to resonant-tunneling diodes, often exhibiting large hysteresis. 14,[18][19][20][21][22][23] A related issue exists for structures operating at zero bias (like absorption structures), especially those of only a few layers: As electrons accumulate in the 2DEG, the active region is depleted. 2,4,16,17 To tackle some of the design problems, we here introduce the two related concepts of polarization balance and polarization-balanced design.…”

Section: Introductionmentioning

confidence: 99%

Polarization-balanced design of heterostructures: Application to AlN/GaN double-barrier structures

2011

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Inversion and depletion regions generally form at the interfaces between doped leads (cladding layers) and the active region of polar heterostructures like AlN/GaN and other nitride compounds. The band bending in the depletion region sets up a barrier that may seriously impede perpendicular electronic transport. This may ruin the performance of devices such as quantum-cascade lasers and resonant-tunneling diodes. Here we introduce the concepts of polarization balance and polarization-balanced designs: A structure is polarization balanced when the applied bias match the voltage drop arising from spontaneous and piezeolectric fields. Devices designed to operate at this bias have polarization-balanced designs. These concepts offer a systematic approach to avoid the formation of depletion regions. As a test case, we consider the design of AlN/GaN double-barrier structures with AlxGa 1−x N leads. To guide our efforts, we derive a simple relation between the intrinsic voltage drop arising from polar effects, average alloy composition of the active region, and the alloy concentration of the leads. Polarization-balanced designs secure good filling of the ground state for unbiased structures, while for biased structures with efficient emptying of the active region they remove the depletion barriers.

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AlN/GaN double-barrier resonant tunneling diodes grown by metal-organic chemical vapor deposition

Cited by 92 publications

References 22 publications

Principle of direct van der Waals epitaxy of single-crystalline films on epitaxial graphene

Principle of direct van der Waals epitaxy of single-crystalline films on epitaxial graphene

Coherent vertical electron transport and interface roughness effects in AlGaN/GaN intersubband devices

Polarization-balanced design of heterostructures: Application to AlN/GaN double-barrier structures

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