Improving the Efficiency of Gallium Telluride for Photocatalysis, Electrocatalysis, and Chemical Sensing through Defects Engineering and Interfacing with its Native Oxide

Abstract

Gallium telluride (GaTe) is a van der Waals semiconductor, currently adopted for photonic and optoelectronic devices. However, the rapid degradation of GaTe in air, promoted by Te vacancies, is detrimental for device applications. Here, it is demonstrate that the surface oxidation of GaTe can be unexpectedly exploited for expanding the breadth of applications of GaTe. Specifically, the formation of a nanoscale sub-stoichiometric wide-band-gap Ga 2 O 3 skin, promoted by Te vacancies, over narrow-band-gap GaTe x upon air exposure is beneficial for electrocatalysis, photocatalysis, and gas sensing . In particular, the Heyrovsky step (H ads + H + + e − → H 2 ) of hydrogen evolution reaction in an acidic medium is barrier-free for the sub-stoichiometric gallium-oxide/ gallium-telluride heterostructure, which also enables a significant reduction of costs with respect to state-of-the-art Pt/C electrodes. In the photocatalytic process, the photo-generated electrons migrate from GaTe to Ga 2 O x skin, which acts as the chemically active side of the interface. Moreover, the Ga 2 O 3 / GaTe heterostructure is a suitable platform for sensing of H 2 O, NH 3 , and NO 2 at operational temperatures extended up to 600 °C (useful for gas detection in combustion processes), mainly due to the increased area of charge redistribution after adsorption achieved upon oxidation of GaTe.

Growth Temperature Effects in Nanoscale-Thick GaTe Films on c-Sapphire Substrate by Molecular Beam Epitaxy: Implications for High-Performance Optoelectronic Devices

“…Notably, at optimized higher temperatures, GaTe maintains its preferred monoclinic structure, although GaTe exhibits poor environmental stability. 44,45 Even then we could not see the additional peak of any oxide or other phases of GaTe such as Ga 2 O 3 or TeO 2 or Ga 2 Te 3 . 32,45,46 So, the absence of additional diffraction peaks from impurities serves as strong evidence of the high purity of the samples.…”

Broadband Photodetection of Centimeter-Scale T-Phase Gallium Telluride Grown by Molecular Beam Epitaxy

“…Currently, 2D GaTe has two crystal structures: m-GaTe and h-GaTe, as shown in Figure a,b, respectively. The layer configuration of GaTe consists of a quadruple layer containing four atomic layers of Te–Ga–Ga–Te. , For h-GaTe, the Ga–Ga bonds are completely perpendicular to the layer plane with an atomic stacking sequence of ABBA, forming a hexagonal crystal structure . On the other hand, m-GaTe presents a twisted posture, with one-third of the Ga–Ga bond in the structure changing from an out-of-plane position to an in-plane position .…”

Improved Charge Transfer for NO2 Gas Sensors by Using 0D SnS Quantum Dot/2D WSe2 Heterostructures

“…Furthermore, it has been found that introducing QDs to the surface of 2D nanomaterials increases the number of activation sites in 2D materials. As a result, most of the researchers are trying to make ultrasensitive detectors by using such heterojunctions. , There are several articles based on innovative 2D semiconductors, and their heterostructure sensor has been reported in the last few years. − The research may have used a specific research design or methodology that has limitations. For example, the research may have relied on self-report measures, which could be subject to biases or may not fully capture the complexity of the phenomenon under investigation.…”