Surface alloying and superstructures of Pb on Cu(100)

Nagl, C.; Platzgummer, Elmar; Haller, O.; Schmid, Michael; Варга, П.

doi:10.1016/0039-6028(95)00387-8

Cited by 103 publications

(75 citation statements)

References 13 publications

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“…A more recent LEED I-V analysis by Gauthier et al [9], including new information from ST!Minvestigations by Nagl et al [14] and Roberts et al [15], provides compelling evidence that the c(4x4) phase is not an overlayer phase, but a surface alloy consisting of Pb chains within the first layer of Cu ( Fig. lb) and where three Pb atoms have substituted for four of the eight c(4x4) Cu atoms.…”

Section: Background On the Pb/cu(100) Systemmentioning

confidence: 97%

“…Hosler et al [4,6], low energy ion scattering (LEIS) studies by Platzgrummer et al [12], and STM analysis by Nagl et al [14] and Roberts et al [15] (all conducted at or below room temperature) show that the c(2x2) phase is essentially an overlayer structure with Pb atoms residing on top of the CU(1OO) surface layer in every other four-fold hollow site (Fig. lc).…”

Section: Background On the Pb/cu(100) Systemmentioning

confidence: 98%

“…From that and several subsequent investigations, atomic structures of the overlayers were identified and are shown in Fig 1. Initially Pb substitutes into Cu surface sites in a one to one ratio [14] leadlng to a less intense and less sharp 1x1 LEED pattern than that of clean Cu(l 00). The lowest coverage ordered phase produces a c(4x4) LEED pattern and corresponds to a Pb coverage of 0.375 monolayer.…”

Section: Background On the Pb/cu(100) Systemmentioning

confidence: 99%

“…In this conversion the addition of one more Pb atom to the c(4x4) unit cell, plus the rearrangement of two of the Pb atoms already there, leads to the removal of the remaining four Cu atoms. Further Pb deposition causes the c(2x2) overlayer to disorder through the introduction of surface dislocation lines [4,7,14], resulting in initial splitting of the 2x2 spots and, eventually, a diffuse (1x1) LEED pattern. Near 0.6 ML a third ordered overlayer structure appears, with a c(5~2x~2)R45" diffraction pattern.…”

Section: Background On the Pb/cu(100) Systemmentioning

confidence: 99%

“…Previous investigations by low energy electron diffraction (LEED) [1][2][3][4][5][6][7][8][9][10], He atom scattering [11][12][13], scanning tunneling microscopy (STM) [14,15] and Rutherford backscattering [16] have established that Pb grows on CU(1OO) in a prototypical StranskiKrastanov mode with three well-defined ordered structures at submonolayer coverages.…”

Section: Introductionmentioning

confidence: 99%

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Surface morphology changes during Pb deposition on Cu(100): evidence for surface alloyed Cu(100)–c(2×2) Pb

Plass

Kellogg

2000

Surface Science

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e describe the rnicrofabrication of a multi-level diffractive optical element (DOE) onto a micro-electromechanical system (MEMS) as a key element in an integrated compact optical-MEMS laser scanner. The DOE is a four-level off-axis microlens fabricated onto a movable polysilicon shuttle. The microlens is patterned by electron beam lithography and etched by reactive ion beam etching. The DOE was fabricated on two generations of MEMS components. The first generation design uses a shuttle suspended on springs and displaced by a linear rack. The second generation design uses a shuttle guided by roller bearings and driven by a single reciprocating gear. Both the linear rack and the reciprocating gear are driven by a microengine assembly. The compact design is based on mounting the MEMS module and a vertical cavity surface emitting laser (VCSEL) onto a fused silica substrate that contains the rest of the optical system. The estimated scan range of the system is &4°with a spot size of 0.5 mm. INTRODUCTIONMicro-electromechanical systems (MEMS) is a primarily silicon-based technology that brings precision motion to the microscopic scale using batch fabrication processes developed as extensions from the silicon integrated circuit industry. Compared to the macroscopic systems whose functions they emulate, MEMS are smaller, lighter, lower cost, and more efficient (lower power consumption). For many applications, it is desirable to incorporate optical functions with MEMS. This requires a hybrid approach to integrate compound semiconductor-based light emitters and some form of rnicrooptics, e.g., diffractive optical elements (DOES), to create an integrated microsystem.Integrated Microsystems is an emerging technology in which electrical, optical, and mechanical functions are combined at the chip level into compact, lightweight, and [ultimately] low cost modules with performance equal to or even exceeding those of conventional macroscopic systems. The development of integrated rnicrosystems is expected to revolutionize abroad range of fields, extending beyond electro/optomechanical systems to the fields of biology, chemistry and medicine. Just as the integrated circuit combines formerly discrete devices (transistors, resistors, capacitors) onto a single chip with increasing functionality at DISCLAIMERPortions of this document may be illegible in electronic image products.Images are produced from the best available original document. AbstractUsing Low Energy Electron Microscopy (LEEM), we have followed Cu(l 00) surface morphology changes during Pb deposition at different temperatures. Surface steps advance and 2-D islands nucleate and grow as deposited Pb first alloys, and then dealloys, on a 125°C CU(1OO) surface. From LEEM images, we determine how much Cu is being displaced at each stage and find that the amount of material added to the top layer for a complete Pb/Cu(100) c(4x4) reconstruction (a surface alloy) is consistent with the expected c(4x4) Cu content of 0.5 monolayer. However, as the surface changes to the Pb/Cu...

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Section: Background On the Pb/cu(100) Systemmentioning

confidence: 97%