Single-electron transistors in GaN/AlGaN heterostructures
17 July 2006
We report transport properties of two single-electron transistors (SETs) on a GaN/AlGaN heterostructure. The first SET formed accidentally in a quantum point contact near pinchoff. Its small size produces large energy scales: a charging energy of 7.5meV, and well-resolved excited states. The second, intentionally- fabricated SET is much larger. More than one hundred uniformly- spaced Coulomb oscillations yield a charging energy of 0.85meV. Excited states are not resolvable in Coulomb diamonds, and the Coulomb blockade peak height remains constant with increasing temperature, indicating that the transport is through multiple quantum levels even at the 450mK base electron temperature of our measurements