Tunnel-barrier rectifiers for optical nantennas

We present comprehensive experimental and theoretical work on tunnel-barrier rectifiers comprising double (Nb2O5-Al2O3) and triple (Ta2O5-Nb2O5-Al2O3) insulator configurations engineered to enhance low-voltage nonlinearity. The key rectifier properties, asymmetry, nonlinearity and responsivity have been assessed from current-voltage measurements. A superior low-voltage asymmetry (12 at 0.1 V) and responsivity (5 A/W at 0.2 V) for MIIIM rectifiers have been observed. The results demonstrate enhanced rectification by atomically multi-layering tunnel barriers in cascaded and non-cascaded MIIIM arrangements, for inclusion in optical nantennas.