Polarization engineered 1-dimensional electron gas arrays

One-dimensional electron gas based devices are of great interest due to their promise in high-performance electronics and future device applications. However, synthesis and patterning of arrays of nanowires is a challenge in all material systems. Here we demonstrate a novel system based on vicinal AlGaN/GaN heterostructures that enables direct electrostatic tuning of the dimensionality of electrons from 1 D to 2 D. Our approach, based on polarization engineering, enables top-down fabrication of dense arrays of pure 1-dimensional electron channels with carrier confinement equivalent to 90 meV, that are capable of carrying technologically relevant current densities up to 130 mA/mm. A direction-dependent small-signal capacitance-voltage profiling to probe the Fermi occupation function of electron gas was used to demonstrate distinct signatures of 1-dimensional density of states and transport in these structures at room temperature. The system discussed here is based on polarization-induced anisotropic charge in vicinal AlGaN/GaN heterostructures. We developed a 2-sub-band model consisting of 1-D and 2-D sub-bands to describe the behavior of these wires. We find excellent agreement between our model and experimental data, confirming the channels are indeed 1-dimensional. Our demonstration of 1-dimensional electron channel arrays in this system could enable optical, electronic and magnetic devices with added functionalities and performance. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3687938]