(111) Surface tensions of III–V compounds and their relationship to spontaneous bending of thin crystals

Cahn, John W.; Hanneman, R. E.

doi:10.1016/0039-6028(64)90006-8

Cited by 103 publications

(43 citation statements)

References 11 publications

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“…In an earlier study conducted by Cahn and Hanneman, [36] a theory was presented for explaining the spontaneous bending of thin III±V semiconducting crystals, such as InSb, which has In-terminated (111) and Sbterminated (111) surfaces. This model is based on the difference in surface tensions/energies on the In-and Sb-terminated surfaces.…”

Section: Nanobowsmentioning

confidence: 99%

Semiconducting and Piezoelectric Oxide Nanostructures Induced by Polar Surfaces

Wang¹,

Kong

Ding

et al. 2004

Adv Funct Materials

578

349

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Zinc oxide, an important semiconducting and piezoelectric material, has three key characteristics. First, it is a semiconductor, with a direct bandgap of 3.37 eV and a large excitation binding energy (60 meV), and exhibits near‐UV emission and transparent conductivity. Secondly, due to its non‐centrosymmetric symmetry, it is piezoelectric, which is a key phenomenon in building electro‐mechanical coupled sensors and transducers. Finally, ZnO is bio‐safe and bio‐compatible, and can be used for biomedical applications without coating. With these unique advantages, ZnO is one of the most important nanomaterials for integration with microsystems and biotechnology. Structurally, due to the three types of fastest growth directions—<0001>, <01$ \bar 1 $0>, and <2$ \bar 1 $$ \bar 1 $0>—as well as the ±(0001) polar surfaces, a diverse group of ZnO nanostructures have been grown in our laboratory. These include nanocombs, nanosaws, nanosprings, nanorings, nanobows, and nanopropellers. This article reviews our recent progress in the synthesis and characterization of polar‐surface‐induced ZnO nanostructures, their growth mechanisms, and possible applications as sensors, transducers, and resonators. It is suggested that ZnO could be the next most important nanomaterial after carbon nanotubes.

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Section: Nanobowsmentioning

confidence: 99%

Semiconducting and Piezoelectric Oxide Nanostructures Induced by Polar Surfaces

Wang¹,

Kong

Ding

et al. 2004

Adv Funct Materials

578

349

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“…The straininduced roughening transition from a planar to a 3D growth mode has been explained by competition between increasing surface energy and decreasing stored elastic strain energy through relaxation at 3D island edges. Since the pioneering work of Asaro and Tiller, refinements of the models [18,19] have led to the concept of a characteristic wavelength λ c for the surface perturbation: the following relationship, λ c = πγ/(1 + ν)E is obtained, where γ is the surface tension per unit area and E is the strain energy per unit volume; E = [21] for InAs, and ε = 0.031 and inserting these quantities, yields a value for λ c of approximately 315 Å, which is in reasonable agreement with our STM results (280 Å). Wire width (Å) Frequency Fig.…”

mentioning

confidence: 99%

Strain-induced formation of self-assembled nanostructures in the epitaxial growth of InAs and GaAs on InP(001)

Robach¹,

Phaner²,

Solère³

et al. 1998

Applied Physics A: Materials Science & Processing

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The evolution of surface morphology in epitaxial InAs and GaAs strained layers grown on InP(001) was investigated by scanning tunneling microscopy. For compressive InAs layers, well-defined nanowires were formed at the onset of the 2D/3D growth mode transition. These wires have base width and height distributions peaked at around 230 Å and 20 Å, respectively. The sharp 2D/3D transition is associated with a large reorganization of matter. In contrast, for tensile GaAs layers the growth mode is characterized by a gradual roughening process.There is increasing interest in the formation of low-dimensional semiconductor structures, such as quantum dots or wires, which, due to quantum confinement effects, exhibit novel physical properties leading to important applications in optoelectronics. One of the promising paths towards the formation of such nanostructures is to exploit spontaneous self-organization phenomena in the early stages of the heteroepitaxial growth of strained semiconductor layers. For a relatively high intrinsic strain, the growth evolves beyond a critical thickness from an initial layer-by-layer growth mode to the formation of coherent 3D islands (Stranski-Krastanov growth mode). This strain-induced self-assembling method has been applied to a wide range of III-V heterostructures, such as In 1−x Ga x As/GaAs [1][2][3][4] or InP/GaAs [5,6]. Quantum dots which exhibit ordering in size, shape and lateral arrangement have been successfully produced by both the metalorganic vapor-phase epitaxy (MOVPE) and molecular beam epitaxy (MBE) growth methods, and their optical properties have been largely characterized [7,8]. Although it was suggested by Tersoff et al.[9] that quantum wires might even be formed in that way, most studies of quantum wire formation have concentrated on the controlled epitaxial growth on patterned or vicinal surfaces [10][11][12]. For optoelectronic applications significant progress must still be achieved to control the size distribution of these 3D nanostructures. Therefore, * Corresponding author a good understanding of the physical processes that govern the strain-induced 3D islanding remains a real challenge.The In 1−x Ga x As/InP system offers a particularly interesting situation because it allows us to study the epitaxial growth of either compressively strained (x < 0.47) or tensilely strained (x > 0.47) layers. In that system the maximum attainable strain corresponds to compressively strained InAs/InP(001) layers (ε = −3.1%) and tensilely strained GaAs/InP(001) layers (ε = 3.7%). We study here the initial stages of growth for these two extreme cases, using scanning tunneling microscopy (STM) to characterize the growing crystal surface. The formation, in the compression case, of well-ordered nanowires at the onset of the 2D/3D growth mode transition will be more particularly described.Epitaxial layers were grown by molecular beam epitaxy in a RIBER 2300 system connected under ultrahigh vacuum to an STM chamber equipped with a beetle-type scanning tunneling microscope [13]. After t...

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“…Surface stress is defined as the variation of the surface free energy with respect to strain and is a two-dimensional, second order tensor. Physically, nonzero surface stresses arise because the atomic configurations and atomic bonding on the surface differs from those in the bulk crystal (Cahn and Hanneman, 1964). In non-centrosymmetric crystals, opposite crystal faces may have different surface stresses.…”

Section: Surface Stressmentioning

confidence: 99%