posted on 2023-11-30, 19:37authored byMuhammad Rabeel, Honggyun Kim, Muhammad Asghar Khan, Muhammad Abubakr, Ibtisam Ahmad, Muneeb Ahmad, Shania Rehman, Myoung-Jae Lee, Muhammad Farooq Khan, Deok-kee Kim
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 (MoTe2) 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-MoTe2 and thick-MoTe2 act as strongly p- and n-type semiconductors,
respectively. The effect of bromine (Br) on the MoTe2 surface
showed efficient p-type doping on thin-MoTe2, leading to
an improved current rectification ratio. The rectification ratio of
the pristine device (1.18 × 103) increased by the
order of 102 after bromine adsorption (4.66 × 105) at Vg = −20 V. The gate-tunable
photodetection of the lateral homojunction MoTe2 diode
demonstrated remarkable photoresponsivity (58.4 AW–1), external quantum efficiency (19,840.95%), and detectivity (2.53
× 1011 Jones). We also successfully demonstrated the
fabrication of the homojunction MoTe2 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 MoTe2 lateral homojunctions, with
potential applications in optoelectronics and future wearable technology.