TY - JOUR
T1 - Properties of interfaces of diamond
AU - Nemanich, R. J.
AU - Bergman, L.
AU - Turner, K. F.
AU - van der Weide, J.
AU - Humphreys, T. P.
N1 - Funding Information:
R. Markunas of RTI for helpful discussions. This work is supported in part by the ONR through grants N00014-92-J-1477, N00014-90-J-1604 and N00014-90-J-1707, the NSF through grant DMR 9204285 and the MIT1 of Japan through the NED0 program.
PY - 1993/4
Y1 - 1993/4
N2 - Results related to two different interface aspects involving diamond are described: (1) the initial states of CVD diamond film growth, and (2) the negative electron affinity and formation of metal-diamond interfaces. The surface and interface properties are probed with STM, Raman scattering/photoluminescence and angle-resolved UV photoemission spectroscopy (ARUPS). STM measurements of diamond nuclei on Si after various plasma growth processes show both flat and hillocked structures characteristics of 2-dimensional and 3-dimensional growth modes, respectively. STS measurements show distinct I-V characteristics of the nuclei and the substrate. The presence of optical defects and the diamond quality are studied with micro-Raman/photoluminescence measurements. The results indicate an increased density of impurity-related defects during the initial stages of growth. The interface properties of Ti on natural crystal (1 1 1) and (1 0 0) surfaces are studied with ARUPS using 21.2 eV HeI emission. Prior to deposition the diamond (1 1 1) is chemically cleaned, and a sharp (0.5 eV FWHM) peak is observed at the position of the conduction band minimum, indicating a negative electron affinity surface. After a subsequent argon plasma clean this peak disappears, while the spectrum shows a shift of 0.5 eV towards higher energies. Upon sub-monolayer titanium deposition on (1 1 1) diamond, the negative electron affinity peak reappears. Further titanium depositions causes this titanium-induced negative electron affinity peak to be attenuated, indicating that the emission originates from the interface. A similar experiment, done on the diamond (1 0 0) surface, however, does not result in a negative electron affinity. By determining the relative positions of the diamond valence band edge and the titanium Fermi level, the Schottky barrier height of titanium on diamond is measured. A model, based on the Schottky barrier height of titanium on diamond, and the work function of titanium, is proposed for the observed titanium-induced negative electron affinity.
AB - Results related to two different interface aspects involving diamond are described: (1) the initial states of CVD diamond film growth, and (2) the negative electron affinity and formation of metal-diamond interfaces. The surface and interface properties are probed with STM, Raman scattering/photoluminescence and angle-resolved UV photoemission spectroscopy (ARUPS). STM measurements of diamond nuclei on Si after various plasma growth processes show both flat and hillocked structures characteristics of 2-dimensional and 3-dimensional growth modes, respectively. STS measurements show distinct I-V characteristics of the nuclei and the substrate. The presence of optical defects and the diamond quality are studied with micro-Raman/photoluminescence measurements. The results indicate an increased density of impurity-related defects during the initial stages of growth. The interface properties of Ti on natural crystal (1 1 1) and (1 0 0) surfaces are studied with ARUPS using 21.2 eV HeI emission. Prior to deposition the diamond (1 1 1) is chemically cleaned, and a sharp (0.5 eV FWHM) peak is observed at the position of the conduction band minimum, indicating a negative electron affinity surface. After a subsequent argon plasma clean this peak disappears, while the spectrum shows a shift of 0.5 eV towards higher energies. Upon sub-monolayer titanium deposition on (1 1 1) diamond, the negative electron affinity peak reappears. Further titanium depositions causes this titanium-induced negative electron affinity peak to be attenuated, indicating that the emission originates from the interface. A similar experiment, done on the diamond (1 0 0) surface, however, does not result in a negative electron affinity. By determining the relative positions of the diamond valence band edge and the titanium Fermi level, the Schottky barrier height of titanium on diamond is measured. A model, based on the Schottky barrier height of titanium on diamond, and the work function of titanium, is proposed for the observed titanium-induced negative electron affinity.
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U2 - 10.1016/0921-4526(93)90290-M
DO - 10.1016/0921-4526(93)90290-M
M3 - Article
AN - SCOPUS:0027576464
SN - 0921-4526
VL - 185
SP - 528
EP - 538
JO - Physica B: Physics of Condensed Matter
JF - Physica B: Physics of Condensed Matter
IS - 1-4
ER -