Capillary tunneling characteristics of aromatic halides on gallium electrodes

The tunneling characteristics based on the capillary tunnel junctions of aromatic halides such as C
6
H
4
C
l2
, C
12
H
8
C
l2
, C
6
H
4
Br
2
, C
12
H
8
Br
2
, C
6
H
4
I
2
, C
12
H
8
I
2
sandwiched between gallium electrodes were described. The current-voltage (I–V) characteristics of the tunnel junctions fabricated by this method show fine rectifying behavior. We compare the conductance of different terminal atom-gallium combinations and find that the conductance is larger when the tunnel junction is assembled by iodine rather than bromine or chlorine. We also find that the tunneling characteristics of functional molecular depend on the number of phenyls. The same trend of HOMO-LUMO energy gap theoretically calculated from functional molecules by the Gaussian 98 package is observed. The results indicate that the nature of functional molecules could significantly contribute to the conductance characteristics of molecular junctions.