The electronic structure of 1,2-PCB₁₀H₁₁ molecular films: a precursor to a novel semiconductor

Authors

Snjezana Balaz, University of Nebraska-LincolnFollow
D.I. Dimov, University of Salford, Salford, UK
N.M. Boag, University of Nebraska-Lincoln
K. Nelson, University of Nebraska-Lincoln
B. Montag, University of Nebraska-Lincoln
Jennifer I. Brand, University of Nebraska-LincolnFollow
Peter A. Dowben, University of Nebraska-LincolnFollow

Date of this Version

4-9-2006

Comments

Published in Applied Physics A 84 (2006), pp. 149–159. Copyright © Springer-Verlag 2006. Used by permission. http://www.springerlink.com/content/1432-0630/.

Abstract

The band gaps and electronic structure of un doped films of molecular icosahedra of closo-1-phospha-2 carbadodecaborane (1,2-PCB₁₀H₁₁) are reported. 1,2-PCB₁₀H₁₁ adsorbs on Au and Ag substrates to generate molecular thin films with the Fermi level(chemical potential) placed closer to the lowest unoccupied molecular orbital than has been observed with closo-1,2-dicarbadodecaborane (1,2-C₂B₁₀H₁₂, orthocarborane) adsorbed on Co, Cu or Ag. Both 1,2-PCB₁₀H₁₁ and 1,2-C₂B₁₀H₁₂ molecular films exhibit an unoccupied molecular defect state above the Fermi level. The vibrational modes, observed in infra-red absorption, are close to the values expected for the isolated 1,2-PCB₁₀H₁₁ molecule. Consistent with the placement of the Fermi level in the molecular films, fabrication of heterojunction diodes from partially dehydrogenated 1,2-PCB₁₀H₁₁ indicates that the resultant PCB- ₁₀H₁₁ semiconductor film is more n-type than the corresponding boron carbide semiconductor formed from 1,2-C₂B₁₀H₁₂, orthocarborane.