Transport in split gate MOS quantum dot structures

We have fabricated symmetric 200 nm and asymmetric 100 by 200 nm quantum dots by the split gate technique within a MOSFET structure. DC electrical and magnetotransport measurements were performed at 4.2 K in a liquid-Helium cryostat. It is found that varying the electrochemical potential by changing the bias on a top gate leads to oscillations in the DC conductance through the dot resembling Coulomb blockade peaks, but when the depletion gate biases are swept, these peaks become more complex in nature, exhibiting crossing or anti-crossing behavior.