2D Tellurium Based High‐Performance All‐Optical Nonlinear Photonic Devices

Abstract

Tellurium (Te), as one of the rarest stable solid elements far more common in the universe than on earth, is a p‐type semiconductor with excellent optical properties. Herein, a novel two‐dimensional (2D) Te nanosheets (Ns)‐based air‐stable nonlinear photonic devices: all‐optical switcher and photonic diode, owing to its strong light–matter interaction in the visible‐to‐infrared band are reported. The findings validate that the proposed photonic diode can be utilized for the function of nonreciprocal light propagation in optical telecommunications or integrated photonics. Moreover, 2D Te‐based light‐modulate‐light system is successfully designed to realize “ON” and “OFF” modes for all‐optical switching operation. This work highlights a good promise of 2D Te in the field of nonlinear photonics, leading to an important step toward 2D Te‐based advanced photonics devices. The versatile solution process allows a universal access of 2D Te as a new 2D material in a wider range of photonics device applications such as, detector, modulator, switcher, etc.

Enhanced Photodetection Properties of Tellurium@Selenium Roll‐to‐Roll Nanotube Heterojunctions

“…Monoelemental tellurium (Te), located in group VI A in the periodic table, has attracted great interests over the past decade due to its intriguing properties, such as excellent photoresponse, fast photoconductivity, high thermoelectricity, and piezoelectricity . As a non‐layered material, Te has a chiral‐chain crystal structure, and the individual Te atoms are stacked together by van der Waals forces . Like the famous black phosphorus (BP), Te has a layer‐dependent energy bandgap ( E g ) that can be tuned from ≈0.35 to ≈1.0 eV as the thickness of Te decreases from bulk to monolayer .…”

“…As a non‐layered material, Te has a chiral‐chain crystal structure, and the individual Te atoms are stacked together by van der Waals forces . Like the famous black phosphorus (BP), Te has a layer‐dependent energy bandgap ( E g ) that can be tuned from ≈0.35 to ≈1.0 eV as the thickness of Te decreases from bulk to monolayer . First‐principles density functional theory (DFT) calculations revealed that 2D Te forms a natural stable state with higher carrier mobility ranging from hundreds to thousands of cm 2 V −1 s −1 , comparable to that of molybdenum disulfide (MoS 2 ) .…”

Novel two-dimensional monoelemental and ternary materials: growth, physics and application

“…After that, Te nanostructures based on other substrate such as sapphire, graphene/4H-SiC and HOPG have also be studied in recent years [137][138][139][140][141][142][143]. In general, there are many kinds of synthetic methods, including physical vapor deposition (PVD) [135], MBE [138], LPE [144][145][146], hydrothermal reaction [131,132,147,148], CVD [130] and thermal evaporation deposition [149,150]. Without consideration of the crystal scale, both Lin et al and Wu et al demonstrated free-standing exfoliated Te nanosheets at the size of several hundred nanometers in polarized solvent by ultrasonic bath and centrifugation [144,146].…”

“…In general, there are many kinds of synthetic methods, including physical vapor deposition (PVD) [135], MBE [138], LPE [144][145][146], hydrothermal reaction [131,132,147,148], CVD [130] and thermal evaporation deposition [149,150]. Without consideration of the crystal scale, both Lin et al and Wu et al demonstrated free-standing exfoliated Te nanosheets at the size of several hundred nanometers in polarized solvent by ultrasonic bath and centrifugation [144,146]. To date, they found greater air stability and biocompatibility of Te nanosheets after the functionalization of glutathione (GSH), which can be used in the photodynamic therapy agents.…”

“…Given the various physics of 2D tellurium and tellurene, such as flexibility, stability, high mobility, narrow bandgap and high optical absorption, their applications in FETs [130,137,147,150], photodynamic therapy [144], optical modulator [146], polarized infrared imaging [132], quantum information [131,155], PDs [130,132,136] and solar absorber [159] have been explored in recent years. In 2018, Wu et al showed that thickness-dependent 2D Te FETs exhibited the recorded highest hole mobility of 700 cm 2 · V −1 · s −1 with a moderate on/off ratio of ~10 3 at ambient conditions.…”