54
3 Modification of the Work Function
Fig. 3.18 a Schematic DOS of metal- or carbon-derived electrons near the Fermi level for 4d
transition metal nitrides. b Schematic DOS of metal- or carbon-derived electrons near the Fermi
level for 5d transition metal nitrides
not a smooth function of the composition in binary systems that form the intermetallic
compounds in the phase diagram.
One example of the composition dependence of the work function is shown in
Fig. 3.19a for the Ni–Al system [16], together with its phase diagram. This experimental result was obtained by fabricating a sample by the successive evaporation
of Al and Ni, followed by annealing at 618 K for 16 h to achieve the alloy equilibrium. The change in the composition dependence of the work function as a result of
annealing clearly demonstrates the characteristic behavior of the work function in
intermetallic compounds. Before annealing, the mixture of Ni and Al did not reach
the equilibrium state and its work function showed a relatively smooth composition
dependence. However, after annealing, specific features appeared at around Ni 75 Al 25 ,
3 Modification of the Work Function
Fig. 3.18 a Schematic DOS of metal- or carbon-derived electrons near the Fermi level for 4d
transition metal nitrides. b Schematic DOS of metal- or carbon-derived electrons near the Fermi
level for 5d transition metal nitrides
not a smooth function of the composition in binary systems that form the intermetallic
compounds in the phase diagram.
One example of the composition dependence of the work function is shown in
Fig. 3.19a for the Ni–Al system [16], together with its phase diagram. This experimental result was obtained by fabricating a sample by the successive evaporation
of Al and Ni, followed by annealing at 618 K for 16 h to achieve the alloy equilibrium. The change in the composition dependence of the work function as a result of
annealing clearly demonstrates the characteristic behavior of the work function in
intermetallic compounds. Before annealing, the mixture of Ni and Al did not reach
the equilibrium state and its work function showed a relatively smooth composition
dependence. However, after annealing, specific features appeared at around Ni 75 Al 25 ,