Layer-by-layer etching of mercuric iodide crystals in the atomic force microscope

Lang, Hans Peter; Roßberg, André; Piechotka, M.; Kaldis, E.

doi:10.1016/0022-0248(94)90479-0

Cited by 6 publications

(6 citation statements)

References 7 publications

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“…Other groups have also observed similar phenomena in WSe 2 , 51,52 HgI 2 53 and TaS 2 . Other groups have also observed similar phenomena in WSe 2 , 51,52 HgI 2 53 and TaS 2 .…”

Section: B Stm Imaging Of He + Ion Sputtered Surfacessupporting

confidence: 64%

Scanning tunneling microscopy investigation of nanostructures produced by Ar+ and He+ bombardment of MoS2 surfaces

Park¹,

France²,

Parkinson³

2005

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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Nanostructures were fabricated on natural MoS 2 crystals by bombardment with low doses of Ar + and He + with energies ranging from 100 to 5 keV. The bombarded surfaces were investigated with x-ray photoemission spectroscopy ͑XPS͒ and scanning tunneling microscopy ͑STM͒ in an ultrahigh vacuum environment. The ion exposures were low enough to ensure that the observed nanostructures can be associated with individual ion impacts. Argon ions ͑Ar + ͒ with energies of 100 eV or less remove very few, if any, sulfur atoms from the surface but STM and XPS studies reveal that the electronic structure of the MoS 2 surface is altered. Ar + with energies greater than 100 eV has a higher probability of sputtering sulfur atoms from the surface. The apparent size of the nanostructures in the STM images increased with Ar + energies up to about 1 keV and was dependent on the angle of incidence of the Ar + . Helium ion ͑He + ͒ sputtering of MoS 2 produced similar but smaller nanostructures when compared to Ar + at the same impinged ion energy. STM images showed bright ring-shaped features were created with He + energies greater than 500 eV. On the basis of XPS and current imaging tunneling spectroscopy investigations, the features are assigned to sulfur atom vacancies. A change in the surface doping type from n to p was observed upon light sputtering of the surface.

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“…Other groups have also observed similar phenomena in WSe 2 , 51,52 HgI 2 53 and TaS 2 . Other groups have also observed similar phenomena in WSe 2 , 51,52 HgI 2 53 and TaS 2 .…”

Section: B Stm Imaging Of He + Ion Sputtered Surfacessupporting

confidence: 64%

Scanning tunneling microscopy investigation of nanostructures produced by Ar+ and He+ bombardment of MoS2 surfaces

Park¹,

France²,

Parkinson³

2005

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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“…7 In another study by the same authors, removal of layers occurred via unwinding of steps at a screw dislocation. It was also concluded that evaporation from the surface indeed contributes to the displacement/removal of material from the crystal.…”

Section: Mercuric Iodidementioning

confidence: 99%

“…2 The effects of dopants on the crystal microstructure and the segregation of impurities during the growth process were reported. 7 This phenomenon has been attributed to the high tendency for HgI 2 to undergo c-plane slip between the two successive layers of iodine atoms in the van der Waals gap when compressive loading is applied to the crystal. The crystals tend to evaporate under vacuum conditions, leading to definite changes of the surface topography.…”

Section: Introductionmentioning

confidence: 99%

Layered heavy metal iodides examined by atomic force microscopy

George¹

1996

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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Atomic force microscopy was used to characterize the surface of semi-insulating bismuth tri-iodide, lead iodide, and mercuric iodide crystals. These heavy metal iodides belong to a unique class of materials that provide a wide range of interesting problems that can be studied by atomic force microscopy. They have relatively high vapor pressures and cannot be examined noninvasively in vacuum conditions, such as by electron microscopy. Mercuric, bismuth, and lead iodide are layered materials with van der Waals bonding along the c axis and therefore, like mica, can be easily cleaved to provide fresh atomically flat crystalline surfaces to study. These crystals are soft with a high degree of plasticity and, as a result, the surfaces are easily modified by the cantilever tip. They demonstrate reactivity in ambient air at the surfaces as well as within the van der Waals gap. Freshly cleaved surfaces were examined and it was found that single and multiple atomic layers were easily displaced on the cleaved surfaces in all of the crystals when scanned in both contact and modulated contact mode. The effects of cantilever induced modifications of the surfaces of mercuric, lead, and bismuth iodide were studied by atomic force microscopy and their properties are discussed.

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“…2 This technique was then used extensively in the late 1970s. 10,11 Hence, studies of the surface by scanning force microscopy ͑SFM͒ at ambient pressure and temperature 12,13 can contribute to the understanding of growth mechanisms in this system. Since the equilibrium vapor pressure of HgI 2 is Ϸ10 Ϫ4 mbar at 300 K, investigations of the surface morphology by traditional scanning electron microscopy might change the surface of the crystals drastically.…”

Section: Introductionmentioning

confidence: 99%

Layer-by-layer etching of HgI2 films and crystals by scanning force microscopy

Lang

Erler

Roßberg

et al. 1996

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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Thin films and single crystals of mercuric iodide (α-HgI2) have been investigated by scanning force microscopy. During the scan process, material evaporation is observed proceeding by hole formation and etching at steps. The ratio of etched volume per second and per interaction area between tip and mercuric iodide step edges is found to be constant for hole formation on an HgI2 crystal and for etching at a screw dislocation on HgI2 films. An estimate for the loading of the SFM tip gives a value comparable to the critical resolved shear stress in this material.

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Layer-by-layer etching of mercuric iodide crystals in the atomic force microscope

Cited by 6 publications

References 7 publications

Scanning tunneling microscopy investigation of nanostructures produced by Ar+ and He+ bombardment of MoS2 surfaces

Scanning tunneling microscopy investigation of nanostructures produced by Ar+ and He+ bombardment of MoS2 surfaces

Layered heavy metal iodides examined by atomic force microscopy

Layer-by-layer etching of HgI2 films and crystals by scanning force microscopy

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