Scanning tunneling microscopy of semiconductor clusters

Sarid, Dror; Henson, Tammy D.; Bell, Larry; Sandroff, C. J.

doi:10.1116/1.575387

Cited by 13 publications

(7 citation statements)

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“…Synthesis of PbI 2 Clusters in Solutions. As reported by others, , the starting materials for PbI 2 cluster synthesis are Pb(NO 3 ) 2 and NaI (or KI). These reagents were purchased from Aldrich with a purity of 99 + %.…”

Section: Methodsmentioning

confidence: 85%

“…Sandroff et al have attempted to utilize optical, TEM, and STM techniques to confirm their proposed model of a disklike clusters for PbI 2 , HgI 2 , and BiI 3 layered compounds. However, all the techniques employed have had limited success in obtaining the disk height information.…”

Section: Resultsmentioning

confidence: 99%

“…The study of nanophase materials physically confined in various hosts has attracted much attention in recent years. − Depending upon the physical properties of the confining hosts and the nature of the confined materials, many unique mechanical, thermal, and optical properties have been observed and are related to different types of confinement effects. For example, (1) the physical confinement, the interfacial interaction between guest and host, and the reduction of the physical size of the confined particle can lead to (a) hardness modification of materials; (b) depression of the melting and freezing transition temperatures; and (c) alteration of crystal nucleation and growth characteristics; (2) the quantum confinement of free electrons in metals and excitons in semiconductors can result in the observation of the surface plasma resonance (SPR) and the shifts of the band gap; (3) dielectric confinement gives rise to surface phonons observed in a wide range of nanophase materials.…”

Section: Introductionmentioning

confidence: 99%

“…Sandroff et al investigated layered semiconductor clusters in various solvents. Based upon the optical absorption spectra of the solutions containing PbI 2 and BiI 3 clusters and transmission electron microscopy (TEM) characterization of the cluster size and size distribution, a single-layered and platelet-like cluster model was proposed.…”

Section: Introductionmentioning

confidence: 99%

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Chemical and Size Characterization of Layered Lead Iodide Quantum Dots via Optical Spectroscopy and Atomic Force Microscopy

Tung

Ueda

et al. 1996

J. Phys. Chem.

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Lead iodide (PbI2) clusters were synthesized from the chemical reaction of NaI (or KI) with Pb(NO3)2 in H2O, D2O, CH3OH, and C3H7OH solvents. The observation of absorption features between the 550 and 350 nm region obtained with an integrating sphere strongly suggests PbI2 quantum dot formation in solution. Comparison of spectra of PbI2 clusters in solution with PbI2 clusters formed by impregnation of PbI2 in four different pore-sized porous silica substrates indicates that the PbI2 cluster size in solution is less than 2.5 nm in the lateral dimension. Atomic force microscopy (AFM) measurements of PbI2 solutions deposited on mica and highly oriented pyrolytic graphite surfaces indicate that the clusters are single layered. The measured height is 1.0 ± 0.1 nm, which is ∼0.3 nm larger than the layer thickness observed for the bulk materials. The swollen layer thickness can be attributed to the intralayer contraction from the strong lateral interaction among PbI2 molecules, which is supported by ab initio calculations. Raman scattering measurements of the LO and TO modes of PbI2 in bulk and in the confined state were also conducted in 50−150 cm-1 region. Three bands observed at 74, 96, and 116 cm-1 for the confined materials are assigned to the TO2, LO2, and LO1 modes, respectively. The relatively small red shift in the LO modes for PbI2 in the porous hosts may be caused by the surface phonon of PbI2 nanoparticles confined in the porous silica.

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Section: Methodsmentioning

confidence: 85%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Chemical and Size Characterization of Layered Lead Iodide Quantum Dots via Optical Spectroscopy and Atomic Force Microscopy

Tung

Ueda

et al. 1996

J. Phys. Chem.

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“…Graphite has also been used as a substrate in the study of semiconductor clusters of Pbi 2 and Bii 3 deposited from colloidal suspensions (Sarid et al, 1988), phosphotungstic acid and rhenium carbonyl complexes, and organic molecules such as acetone (Lyding et al, 1988a,b ). In the study of acetone, a complete and ordered monolayer of acetone molecules on graphite was formed after continuous exposure for -24 hours.…”

Section: Graphite As a Substratementioning

confidence: 99%

Scanning Tunneling Microscopy

Neddermeyer¹

1993

Perspectives in Condensed Matter Physics

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represented a revolution in the field of surface science comparable only to the introduction of ultrahigh vacuum (UHV), low-energy electron diffraction (LEED), Auger electron spectroscopy (AES), and other major analytical techniques. STM has already been used to resolve long-standing surface science problems such as the structure of the Si(111) 7x7 surface (Binnig •et al., 1983a). It has demonstrated its ability to image surfaces with atomic resolution in air and in liquid environments. STM has virtually no environment limitations, unlike most other surface science techniques that require UHV for their operation. UHV is necessary for STM when reactive surfaces that would degrade rapidly in non-UHV environments are being studied. STM has apparently unlimited potential in fields beyond the realm of classical surface science. Such fields include the imaging of biological material, atomic-scale electrochemistry, and microengineering. An ever-expanding number of applications, the continuing development of better instruments, and our increasing understanding-both experimentally and theoretically-of the tunneling phenomenon in real systems make STM a rapidly changing field. Thus this chapter is best regarded as a "status report" of the chemical applications of STM.

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Materials Characterization Using Scanning Tunneling Microscopy: From Fundamentals to Advanced Applications

Debata

Das

Madhuri

et al. 2018

Handbook of Materials Characterization

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Scanning tunneling microscopy of semiconductor clusters

Abstract: Articles you may be interested inThe image potential in scanning tunneling microscopy of semiconductor surfaces Summary Abstract: Scanning tunneling microscopy of semiconductor surfaces

Cited by 13 publications

References 0 publications

Chemical and Size Characterization of Layered Lead Iodide Quantum Dots via Optical Spectroscopy and Atomic Force Microscopy

Chemical and Size Characterization of Layered Lead Iodide Quantum Dots via Optical Spectroscopy and Atomic Force Microscopy

Scanning Tunneling Microscopy

Materials Characterization Using Scanning Tunneling Microscopy: From Fundamentals to Advanced Applications

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