A new compilation, based on a literature search for the period 1969–1976, is made of experimental data on the work function. For these 44 elements, preferred values are selected on the basis of valid experimental conditions. Older values, which are widely accepted, are given for 19 other elements on which there is no recent literature, and are so identified. In the data for the 63 elements, trends that occur simultaneously in both the columns and the rows of the periodic table are shown to be useful in predicting correct values and also for identifying questionable data. Several illustrative examples are given, including verifications of predictions published in 1950.

The work function of the elements and its periodicity

The structure and properties of metal-semiconductor interfaces

Photoemission studies of adsorbed oxygen and oxide layers

We study the relaxations, surface energies, and work functions of low-index metallic surfaces using pseudopotential plane-wave density-functional calculations within the generalized gradient approximation. We study here the (100), (110), and (111) surfaces of Al, Pd, Pt, and Au and the (0001) surface of Ti, chosen for their use as contact or lead materials in nanoscale devices. We consider clean, mostly nonreconstructed surfaces in the slab-supercell approximation. Particular attention is paid to the convergence of these quantities with respect to slab thickness; furthermore, different methodologies for the calculation of work functions and surfaces energies are compared. We find that the use of bulk references for calculations of surface energies and work functions can be detrimental to convergence unless numerical grids are closely matched, especially when surface relaxations are being considered. Our results and comparison show that calculated values often do not quantitatively match experimental values. This may be understandable for the surface relaxations and surface energies, where experimental values can have large error but even for the work functions, neither local nor semilocal functionals emerge as an accurate choice for every case.

Surface energies, work functions, and surface relaxations of low index metallic surfaces from first principles

The dependence of the metal gate work function on the underlying gate dielectric in advanced metal-oxide-semiconductor (MOS) gate stacks was explored. Metal work functions on high-κ dielectrics are observed to differ appreciably from their values on SiO2 or in vacuum. We applied the interface dipole theory to the interface between the gate and the gate dielectric of a MOS transistor and obtained excellent agreement with experimental data. Important parameters such as the slope parameters for gate dielectrics like SiO2, Al2O3, Si3N4, ZrO2, and HfO2 were extracted. In addition, we also explain the weaker dependence of n+ and p+ polysilicon gate work functions on the gate dielectric material. Challenges for gate work function engineering are highlighted. This work provides additional guidelines on the choice of gate materials for future MOS technology incorporating high-κ gate dielectrics.

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Metal-dielectric band alignment and its implications for metal gate complementary metal-oxide-semiconductor technology

The electron work function was measured by the Fowler method for four faces of a copper single crystal The crystal was cleaned by repeated cycles of ion bombardment and annealing at 700\ifmmode^\circ\else\textdegree\fi{}C under ultrahigh vacuum conditions With uncertainties of $\ensuremath{\delta}\ensuremath{\Phi}=\ifmmode\pm\else\textpm\fi{}003$ eV, the work functions were found to be ${\ensuremath{\Phi}}_{110}=448$ eV, ${\ensuremath{\Phi}}_{112}=453$ eV, ${\ensuremath{\Phi}}_{100}=459$ eV, and ${\ensuremath{\Phi}}_{111}=494$ eV

P.O. Gartland

Papers

Photoelectric Work Function of a Copper Single Crystal for the (100), (110), (111), and (112) Faces

Anisotropic work function of clean and smooth low-index faces of aluminium

Adsorption of oxygen on clean single crystal faces of aluminium

Photoelectric work function of a molybdenum single crystal for the (100), (110), (111), (112), (114), and (332) faces

Surface-Effect Characteristics of Photoemission from Clean Copper-Crystal Surfaces