abstract
Three different procedures are used to deposit aluminium onto O-terminated (100) and (111) boron-doped diamond, with the aim of producing a thermally stable surface with low work function and negative electron affinity. The methods are 1) deposition of a > 20 nm film of Al by high-vacuum evaporation followed by HCl acid wash to remove excess metallic Al, 2) deposition of <3 angstrom of Al by atomic layer deposition, and 3) thin-film deposition of Al by electron beam evaporation. The surface structure, work function, and electron affinity are investigated after annealing at temperatures of 300, 600, and 800 degrees C. Except for loss of excess O upon first heating, the Al + O surfaces remain stable up to 800 degrees C. The electron affinity values are generally between 0.0 and -1.0 eV, and the work function is generally 4.5 +/- 0.5 eV, depending upon the deposition method, coverage, and annealing temperature. The values are in broad agreement with those predicted by computer simulations of Al + O (sub)monolayers on a diamond surface.
keywords
SCHOTTKY-BARRIER HEIGHT; BORON-DOPED DIAMOND; EMISSION; LAYER; SPECTROSCOPY; METALS; STATES; FILMS
subject category
Physics, Condensed Matter
authors
James, MC; Cattelan, M; Fox, NA; Silva, RF; Silva, RM; May, PW
our authors
Ricardo Manuel Fonseca Lopes da Silva
Junior Researcher
Rui Ramos Ferreira e Silva
Associate Professoracknowledgements
M.C.J. thanks the Engineering and Physical Sciences Research Council (EPSRC) for funding under grant code EP/L016648/1 as part of the Functional Nanomaterials CDT. The authors acknowledge the Bristol NanoESCA Facility (funded by EPSRC Strategic Equipment Grants EP/K035746/1 and EP/M000605/1). The ALD work was developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020 and UIDP/50011/2020, financed by national funds through the Portuguese Foundation for Science and Technology/MCTES.