Heterostructure of Reduced Titanium Dioxide Nanorods and Small Molecules Leads to Photo-Induced Negative Differential Resistance Behaviors

Abstract

Negative differential resistance (NDR) is of considerable interest due to the uncommon characteristic of having a region where the current decreases as the applied voltage bias increases. However, it is difficult to reproduce NDR devices and evaluate their reliability and stability because of the unstable NDR behaviors. In this paper, a highly stable photo-induced hybrid photonic (HP)-NDR device is presented for practical applications, which has heterostructure between TiO2-x nanorods formed by oblique angle deposition and dinaphtho[2,3-b:2 ',3 '-f]-thieno[3,2-b]thiophene. The mechanism of NDR behaviors is investigated through morphological analysis, energy band structure, and electrical characteristics. In addition, diverse bias stress and endurance measurements are performed to demonstrate the reliability of the HP-NDR device. As a result, the NDR behavior lasts up to 1,000 s in each bias stress and 38,850 cycles in the repeated current-voltage (I-V) characteristics Thus, the study has successfully achieved robust HP-NDR devices with potential for practical applications. Utilizing oblique angle deposition technology, a photo-induced NDR device is proposed based on the understanding of NDR behavior. The TiO2-x NRs/DNTT heterostructure-based NDR device is evaluated through various stability assessments, demonstrating robust and stable operation characteristics. image