Studying the lateral composition in Ge quantum dots on Si(001) by conductive atomic force microscopy

Xue, Fei; Qin, Jie; Cui, Jian; Fan, Yong; Yang, Xin

doi:10.1016/j.susc.2005.06.082

Cited by 25 publications

(29 citation statements)

References 14 publications

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“…2a – h , respectively. Before NHH etching, ring-shaped and cross-shaped current distributions are observed on dome and pyramid QDs, respectively, similar to the results reported in our previous papers [ 31 , 32 ]. For simplicity, only the dome-shaped QDs will be concerned afterwards, as the result is similar for pyramid-shaped QDs.…”

Section: Resultssupporting

confidence: 89%

Investigating the Composition and Conductance Distributions on Highly GeSi Mixed Quantum Dots and Inside Oxidation Problem

Ye¹,

Ma²,

Lv³

et al. 2015

Nanoscale Res Lett

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With the help of a nanoscale trench, the composition and conductance distributions of single GeSi quantum dots (QDs) are obtained by conductive atomic force microscopy combined with selective chemical etching. However, the obtained composition and current distributions are unwonted and inconsistent on the QDs grown at 680°C. With a series of confirmatory experiments, it is suggested that a thick oxide layer is formed and remains on the QDs' surface after etching. Though this selective chemical etching has already been widely applied to investigate the composition distribution of GeSi nanostructures, the oxidation problem has not been concerned yet. Our results indicate that the oxidation problem could not be ignored on highly GeSi mixed QDs. After removing the oxide layer, the composition and conductance distributions as well as their correlation are obtained. The results suggest that QDs' current distribution is mainly determined by the topographic shape, while the absolute current values are influenced by the Ge/Si contents.

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Section: Resultssupporting

confidence: 89%

Investigating the Composition and Conductance Distributions on Highly GeSi Mixed Quantum Dots and Inside Oxidation Problem

Ye¹,

Ma²,

Lv³

et al. 2015

Nanoscale Res Lett

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“…The ring-shaped current distribution was interpreted in our previous paper [9]. The main point is that the ring-shaped current distribution is mainly attributed to the high Si-alloyed GeSi composition uniformly distributed in QDs and also the topographic shape effect.…”

Section: Resultsmentioning

confidence: 71%

“…offers an effective way to study the conductive properties of individual QDs [6][7][8], which have already been employed on various QDs, including GeSi [9,10], GaN [11,12], InP [13], TiSi 2 [14], and so on.…”

Section: Introductionmentioning

confidence: 99%

Bias-dependent conductive characteristics of individual GeSi quantum dots studied by conductive atomic force microscopy

Wu¹,

Zhang²,

Lin³

et al. 2011

Nanotechnology

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The bias-dependent electrical characteristics of individual self-assembled GeSi quantum dots (QDs) are investigated by conductive atomic force microscopy. The results reveal that the conductive characteristics of QDs are strongly influenced by the applied bias. At low (-0.5 to - 2.0 V) and high (-2.5 to - 4.0 V) biases, the current distributions of individual GeSi QDs exhibit ring-like and disc-like characteristics respectively. The current of the QD's central part increases more quickly than that of the other parts as the bias magnitude increases. Histograms of the magnitude of the current on a number of QDs exhibit the same single-peak feature at low biases, and double- or three-peak features at high biases, where additional peaks appear at large-current locations. On the other hand, histograms of the magnitude of the current on the wetting layers exhibit the same single-peak feature for all biases. This indicates the conductive mechanism is significantly different for QDs and wetting layers. While the small-current peak of QDs can be attributed to the Fowler-Nordheim tunneling model at low biases and the Schottky emission model at high biases respectively, the large-current peak(s) may be attributed to the discrete energy levels of QDs. The results suggest the conductive mechanisms of GeSi QDs can be regulated by the applied bias.

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“…17 18 The composition distribution can be further supported by the selective etching experiment, as reported previously. 19 The islands were etched by using 30% H 2 O 2 for 30 min at the room temperature, and we found that both the average height and diameter of islands were reduced marginally after etching. This suggests that the most part of the islands contains Si higher than 35% and this high Si concentration is definitely due to Si atoms incorporated into Ge islands during growth at 640 C.…”

Section: Resultsmentioning

confidence: 75%

Composition and Strain Measurements of Ge(Si)/Si(001) Islands by HRTEM

Lin

Wu²,

Tang³

et al. 2009

J. Nanosci. Nanotech.

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The distributions of the composition and the strain in the Ge(Si)/Si(001) coherent islands grown by molecular-beam epitaxy are investigated by digital analysis of high resolution transmission electron microscopy (HRTEM) micrographs. Local composition and strain are obtained from the measurement of the lattice displacement based on the Poisson's formula and Vegard's law. The analysis suggests that the islands have high Ge content at the island's central region. The island is partially relaxed by the substrate deformation and strain concentrated around the edge of islands. The alloying of the islands was found due to the Si surface diffusion.

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Studying the lateral composition in Ge quantum dots on Si(001) by conductive atomic force microscopy

Cited by 25 publications

References 14 publications

Investigating the Composition and Conductance Distributions on Highly GeSi Mixed Quantum Dots and Inside Oxidation Problem

Investigating the Composition and Conductance Distributions on Highly GeSi Mixed Quantum Dots and Inside Oxidation Problem

Bias-dependent conductive characteristics of individual GeSi quantum dots studied by conductive atomic force microscopy

Composition and Strain Measurements of Ge(Si)/Si(001) Islands by HRTEM

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