Broadband and Flexible Photodiode of a Bromine-Doped Lateral MoTe<sub>2</sub> Homojunction
Muhammad Rabeel, Honggyun Kim, Muhammad Asghar Khan, Muhammad Asghar Khan, Muhammad Abubakr, Ibtisam Ahmad, Muneeb Ahmad, Shania Rehman, Myoung‐Jae Lee, Muhammad Farooq Khan, Muhammad Farooq Khan, Deok‐kee Kim
Abstract
The implications of atomically thin-layered two-dimensional (2D) materials for electrical, optical, and flexible applications have great potential for a new-generation technology. Here, we successfully fabricated a flexible and lateral homojunction photodiode using a single molybdenum ditelluride (MoTe 2 ) flake with varying thicknesses (thin–thick). The gate voltage manipulation allowed a significant separation of photocarriers and created a built-in field at the interface, resulting in broadband photodetection from ultraviolet to near-infrared wavelengths. The study found that thin-MoTe 2 and thick-MoTe 2 act as strongly p- and n-type semiconductors, respectively. The effect of bromine (Br) on the MoTe 2 surface showed efficient p-type doping on thin-MoTe 2, leading to an improved current rectification ratio. The rectification ratio of the pristine device (1.18 × 10 3 ) increased by the order of 10 2 after bromine adsorption (4.66 × 10 5 ) at V g = −20 V. The gate-tunable photodetection of the lateral homojunction MoTe 2 diode demonstrated remarkable photoresponsivity (58.4 AW –1 ), external quantum efficiency (19,840.95%), and detectivity (2.53 × 10 11 Jones). We also successfully demonstrated the fabrication of the homojunction MoTe 2 photodiode on a flexible substrate, holding promise for wearable medical optoelectronic devices. Performance evaluation under different bending radii showed slightly reduced responsivity (25.4 AW –1 ) compared to that of the flat surface (27.3 AW –1 ). Thus, this research presents an intriguing approach for high-performance and flexible photodetectors based on MoTe 2 lateral homojunctions, with potential applications in optoelectronics and future wearable technology.