Modified Stranski–Krastanov growth in stacked layers of self-assembled islands

Schmidt, Oliver G.; Kienzle, O.; Hao, Yue; Eberl, K.; Ernst, F.

doi:10.1063/1.123522

Cited by 167 publications

(90 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Here we apply the general results derived above to periodic strained/spacer structure studied in many experiments, [9][10][11][12][13][14][15][16]18 for which, all the strained layers (odd-numbered) consist of the same material A, with the same deposition rate v A and average thickness l A , and the thickness of each spacer layer (even-numbered) is fixed as l B . Thus, from Eq.…”

Section: B Results: Kinetic Critical Thicknessmentioning

confidence: 99%

“…(Typical Ge layers are rather thin and usually expressed in units of monolayers, while the Si spacer layers are relatively thick and appropriately expressed in nanometers, as in experiments. [14][15][16] We use the conversion 1 ML = 0.1457 nm for Ge monolayers 15 in our calculations.) For surface mobility Γ k , the definitive measurement of its absolute value over a range of temperature is lacking, and we determine it from the expression of single-layer result:…”

Section: B Results: Kinetic Critical Thicknessmentioning

confidence: 99%

“…In this system, the strained layers (either tensile or compressive with respect to the substrate) and spacer layers are alternately deposited on a substrate of material B, such as InAs/GaAs(001), [11][12][13] Ge/Si(001), [14][15][16] and SiGe/Si(001). 9,10,18 The strained layers are odd-numbered (i = 1, 3, ...), with nonzero misfit strains ǫ i = 0, while the even-numbered spacer layers (j = 2, 4, ...) are of substrate material B, with zero misfit ǫ j = ǫ B = 0.…”

Section: Strained/spacer Multilayer Structuresmentioning

confidence: 99%

“…For the strained/spacer multilayer structure, a remarkable phenomenon is the vertical self-organization of multisheet arrays of three-dimensional (3D) islands (quantum dots). 1,[9][10][11][12][13][14][15][16][17] The islands are vertically correlated in successive strained layers, with the increasing uniformity (including island size and density) as the number of layers increases. These low-dimensional nanostructures (such as quantum wires and quantum dots), realized through the development of multilayer film instability, exhibit novel electronic and optical properties, including the band structure, carrier transport, etc., and are of intense interests both for fundamental studies and for application to devices with enhanced optoelectronic performance.…”

Section: Introductionmentioning

confidence: 99%

“…1 Currently, two kinds of multilayers are being actively studied: (i) the alternating tensile/compressive multilayers exploited as multiple quantum wells or short-period superlattices; [2][3][4][5][6][7][8] and (ii) multisheets of coherently strained layers (or islands) alternately separated by spacer layers of substrate materials (strained/spacer arrays). 1,[9][10][11][12][13][14][15][16][17][18] Experimentally, these multilayer structures are grown coherently on the substrates, without the generation of undesirable misfit dislocations. When instability occurs and develops during the multilayer films growth, one of the most important phenomena is the formation of self-organized nanostructures.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Stress-driven instability in growing multilayer films

Huang

Desai

2003

Phys. Rev. B

View full text Add to dashboard Cite

We investigate the stress-driven morphological instability of epitaxially growing multilayer films, which are coherent and dislocation-free. We construct a direct elastic analysis, from which we determine the elastic state of the system recursively in terms of that of the old states of the buried layers. In turn, we use the result for the elastic state to derive the morphological evolution equation of surface profile to first order of perturbations, with the solution explicitly expressed by the growth conditions and material parameters of all the deposited layers. We apply these results to two kinds of multilayer structures. One is the alternating tensile/compressive multilayer structure, for which we determine the effective stability properties, including the effect of varying surface mobility in different layers, its interplay with the global misfit of the multilayer film, and the influence of asymmetric structure of compressive and tensile layers on the system stability. The nature of the asymmetry properties found in stability diagrams is in agreement with experimental observations. The other multilayer structure that we study is one composed of stacked strained/spacer layers. We also calculate the kinetic critical thickness for the onset of morphological instability and obtain its reduction and saturation as number of deposited layers increases, which is consistent with recent experimental results. Compared to the single-layer film growth, the behavior of kinetic critical thickness shows deviations for upper strained layers.

show abstract

Section: B Results: Kinetic Critical Thicknessmentioning

confidence: 99%

Section: B Results: Kinetic Critical Thicknessmentioning

confidence: 99%

Section: Strained/spacer Multilayer Structuresmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Stress-driven instability in growing multilayer films

Huang

Desai

2003

Phys. Rev. B

View full text Add to dashboard Cite

show abstract

Electron and Hole Confinement in Stacked Self-Assembled InP Dots of Different Sizes

Hayne

Maes

Manz

et al. 2001

phys. stat. sol. (b)

Self Cite

View full text Add to dashboard Cite

We report photoluminescence (PL) measurements on doubly-stacked layers of self-assembled InP quantum dots. The amount of material in the lower layer is kept constant, whilst in the upper layer it is systematically reduced. Zero-field PL measurements demonstrate that for each stack only one dot (the largest one) is occupied by an electron, and that when the amount of InP in both layers is the same the upper dots are larger. The behaviour of the holes, which are confined by strain in the structure, is revealed by high field (50 T) PL experiments. The holes are found to be increasingly localised to a smaller and smaller volume as the size of the dots in the upper layer is reduced.

show abstract

Self-Ordering of Ge Islands on Si Substrates Mediated by Local Strain Fields

Βrunner

Zhu

Abstreiter

et al. 2001

phys. stat. sol. (b)

Self Cite

View full text Add to dashboard Cite

We have fabricated linear chains and two-dimensional arrays of Ge islands by self-assembling and self-ordering processes on vicinal Si substrates.Step bunches and stripe-like strain fields caused by underlying Si/SiGe multilayers with periodic wire-like accumulations at step edges induce an alignment of Ge islands. Repulsion of neighboring islands is caused by overlapping short-ranged strain fields surrounding partially strain relaxed dots and defines a minimum island separation. A periodic array of wires forming within the multilayer serves as a self-organized template for twodimensionally ordered Ge islands with a lateral period of 120 nm which is comparable to the island size.In the last decade, the epitaxial self-assembly of semiconductor quantum dots by the Stranski-Krastanov growth mode has developed to one of the most powerful techniques for fabricating quantum structures of high quality. The main material systems used are GaAs/InAs and Si/Ge with a lattice mismatch of about 7% and 4%, respectively. The smaller size and effective electron mass for In(Ga)As dots enhances quantum size effects compared to Ge dots. These features and the efficient optical interband transitions favor In(Ga)As quantum dots for optical fundamental studies and future optoelectronic applications [1,2]. A multitude of studies of the fundamental dot formation processes like nucleation, coalescence, ripening, faceting, shape transitions and ordering of dots, however, were performed on Ge islands on (001)Si substrate [3][4][5]. This may be due to the good knowledge of material parameters and the large accessible range of dot size which can be controlled by substrate temperature, Ge content and coverage. Ge islands with a diameter of about 200 nm down to 10 nm and a height of 10 nm to 1 nm were fabricated just by varying the substrate temperature from about 700 to 500 C. They can be embedded in active Si structures without defects and reveal quantum dot related properties, for example in photocurrent spectroscopy of intra valence band transitions in the mid-infrared spectral range and in admittance spectroscopy [6][7][8]. From these studies, hole localization energies around 350 meV, zero-dimensional (0D) hole quantization energies of about 40 meV and Coulomb blockade energies up to 15 meV were deduced for a dot size of about 20 nm. In this paper, we present a study on self-ordering of Ge islands in one-or two-dimensional arrays. The self-organized process of step-bunching in Si/SiGe multilayers on vicinal Si substrates and Ge island nucleation modified by local strain are combined.

show abstract

Modified Stranski–Krastanov growth in stacked layers of self-assembled islands

Cited by 167 publications

References 14 publications

Stress-driven instability in growing multilayer films

Stress-driven instability in growing multilayer films

Electron and Hole Confinement in Stacked Self-Assembled InP Dots of Different Sizes

Self-Ordering of Ge Islands on Si Substrates Mediated by Local Strain Fields

Contact Info

Product

Resources

About