Coaxial Nanowire Resonant Tunneling Diodes from non-polar AlN/GaN on Silicon

TL;DR

This paper reports the fabrication and characterization of AlN/GaN coaxial nanowire resonant tunneling diodes on silicon, demonstrating room temperature negative differential resistance with high current density, and highlights the advantages of non-polar orientations.

Contribution

It introduces non-polar AlN/GaN nanowire heterostructures for resonant tunneling diodes and shows their improved performance over polar structures, including room temperature operation.

Findings

Negative differential resistance observed at cryogenic temperatures.

Room temperature negative differential resistance with high peak current density.

Non-polar nanowire orientation enhances resonant tunneling performance.

Abstract

Resonant tunneling diodes are formed using AlN/GaN core-shell nanowire heterostructures grown by plasma assisted molecular beam epitaxy on n-Si(111) substrates. By using a coaxial geometry these devices take advantage of non-polar (m-plane) nanowire sidewalls. Device modeling predicts non-polar orientation should enhance resonant tunneling compared to a polar structure and that AlN double barriers will lead to higher peak-to-valley current ratios compared to AlGaN barriers. Electrical measurements of ensembles of nanowires show negative differential resistance appearing only at cryogenic temperature. Individual nanowire measurements show negative differential resistance at room temperature with peak current density of 5*10^5 A/cm^2.