Wafer-Scale Carbon Nanotubes Diodes Based on Dielectric-Induced Electrostatic Doping

Diodes based on p–n junctions are fundamental building blocks for numerous circuits, including rectifiers, photovoltaic cells, light-emitting diodes (LEDs), and photodetectors. However, conventional doping techniques to form p- or n-type semiconductors introduce impurities that lead to Coulomb scattering. When it comes to low-dimensional materials, controllable and stable doping is challenging due to the feature of atomic thickness. Here, by selectively depositing dielectric layers of Y₂O₃ and AlN, direct formation of wafer-scale carbon-nanotube (CNT) diodes are demonstrated with high yield and spatial controllability. It is found that the oxygen interstitials in Y₂O₃, and the oxygen vacancy together with Al–Al bond in AlN/Y₂O₃ electrostatically modulate the intrinsic CNTs channel, which leads to p- and n-type conductance, respectively. These CNTs diodes exhibit a high rectification ratio (>10⁴) and gate-tunable rectification behavior. Based on these results, we demonstrate the applicability of the diodes in electrostatic discharge (ESD) protection and photodetection.