Detection of Si doping in the AlN/GaN MQW using Super X – EDS measurements

Sobczak, Kamil; Borysiuk, J.; Strąk, Paweł; Jakieła, R.; Koronski, Kamil; Kamińska, A.; Monroy, E.; Krukowski, S.

doi:10.1016/j.micron.2020.102864

Cited by 5 publications

(5 citation statements)

References 23 publications

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“…Clearly, there is a correlation between the HAADF image and the EDX signal mapping the presence of Si, presented in Figure b. Quantification of the Si content in the arm was performed according to the approach verified previously . Average Si doping in the surrounding is taken as n = 1 × 10 20 cm –3 .…”

Section: Resultsmentioning

confidence: 99%

“…The measurements were performed in scanning TEM (STEM) mode using a high-angle annular dark-field (HAADF) detector. Composition measurements were carried out using EDX spectroscopy Super-X (Bruker BD4) with the approach proven previously to provide excellent precision in determination of local Si dopant concentration in nitride structures …”

Section: Methodsmentioning

confidence: 99%

“…Composition measurements were carried out using EDX spectroscopy Super-X (Bruker BD4) with the approach proven previously to provide excellent precision in determination of local Si dopant concentration in nitride structures. 33 ■ RESULTS AND DISCUSSION Surface Morphology of GaN:Si Layers Grown by PAMBE under Metal-Rich Conditions. The surface morphology of the GaN:Si layers doped to three different levels, 1 × 10 19 , 5 × 10 19 , and 1 × 10 20 cm −3 , is shown in Figure 1.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

“…Quantification of the Si content in the arm was performed according to the approach verified previously. 33 Average Si doping in the surrounding is taken as n = 1 × 10 20 cm −3 . The Si signal intensity measured within the star-arm area was compared with the reference Si signal intensity in the star surrounding.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

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Nanostars in Highly Si-Doped GaN

Sawicka

Turski

Sobczak

et al. 2023

Crystal Growth & Design

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Understanding the relation between surface morphology during epitaxy of GaN:Si and its electrical properties is important from both the fundamental and application perspectives. This work evidences the formation of nanostars in highly doped GaN:Si layers with doping level ranging from 5 × 1019 to 1 × 1020 cm–3 grown by plasma-assisted molecular beam epitaxy (PAMBE). Nanostars are 50-nm-wide platelets arranged in six-fold symmetry around the [0001] axis and have different electrical properties from the surrounding layer. Nanostars are formed in highly doped GaN:Si layers due to the enhanced growth rate along the a-direction ⟨112̅0⟩. Then, the hexagonal-shaped growth spirals, typically observed in GaN grown on GaN/sapphire templates, develop distinct arms that extend in the a-direction ⟨112̅0⟩. The nanostar surface morphology is reflected in the inhomogeneity of electrical properties at the nanoscale as evidenced in this work. Complementary techniques such as electrochemical etching (ECE), atomic force microscopy (AFM), and scanning spreading resistance microscopy (SSRM) are used to link the morphology and conductivity variations across the surface. Additionally, transmission electron microscopy (TEM) studies with high spatial resolution composition mapping by energy-dispersive X-ray spectroscopy (EDX) confirmed about 10% lower incorporation of Si in the hillock arms than in the layer. However, the lower Si content in the nanostars cannot solely be responsible for the fact that they are not etched in ECE. The compensation mechanism in the nanostars observed in GaN:Si is discussed to be an additional contribution to the local decrease in conductivity at the nanoscale.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: ■ Experimental Sectionmentioning

confidence: 99%

Section: ■ Experimental Sectionmentioning

confidence: 99%

See 2 more Smart Citations

Nanostars in Highly Si-Doped GaN

Sawicka

Turski

Sobczak

et al. 2023

Crystal Growth & Design

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“…These conclusions were supplemented by conventional and high-resolution scanning transmission electron microscopy ((S)TEM), observations that were performed in a system, TITAN CUBED 80-300 microscope, working at 300 kV and equipped with Cs-corrector and high-angle annular dark-field (HAADF) detector. These data provide information on the well and barrier thickness and chemical composition [ 12 , 13 , 47 ]. TEM analysis confirmed high quality of the samples and full agreement of their geometry with the designed structures.…”

Section: The Experimental Verificationmentioning

confidence: 99%

Critical Evaluation of Various Spontaneous Polarization Models and Induced Electric Fields in III-Nitride Multi-Quantum Wells

et al. 2021

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In this paper, ab initio calculations are used to determine polarization difference in zinc blende (ZB), hexagonal (H) and wurtzite (WZ) AlN-GaN and GaN-InN superlattices. It is shown that a polarization difference exists between WZ nitride compounds, while for H and ZB lattices the results are consistent with zero polarization difference. It is therefore proven that the difference in Berry phase spontaneous polarization for bulk nitrides (AlN, GaN and InN) obtained by Bernardini et al. and Dreyer et al. was not caused by the different reference phase. These models provided absolute values of the polarization that differed by more than one order of magnitude for the same material, but they provided similar polarization differences between binary compounds, which agree also with our ab initio calculations. In multi-quantum wells (MQWs), the electric fields are generated by the well-barrier polarization difference; hence, the calculated electric fields are similar for the three models, both for GaN/AlN and InN/GaN structures. Including piezoelectric effect, which can account for 50% of the total polarization difference, these theoretical data are in satisfactory agreement with photoluminescence measurements in GaN/AlN MQWs. Therefore, the three models considered above are equivalent in the treatment of III-nitride MQWs and can be equally used for the description of the electric properties of active layers in nitride-based optoelectronic devices.

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