Properties of Sn/BeO heterostructure formed with beryllium oxide (BeO) monolayer and 2D stanene (Sn) is studied in this work. The first-principle study is employed here to systematically investigate the structural stability and electrical properties of the Sn/BeO heterostructure. The results from simulations reveal that the introduction of BeO not only leads to a significant bandgap opening of 98 meV, but it also retains the various intrinsic electrical properties of stanene to a large extent. The effect of spin-orbit coupling (SOC) is studied both in pristine stanene as well as in Sn/BeO heterostructure. The Sn/BeO heterostructure shows the Rashba-type of spin-splitting under SOC, which is very promising for application in spintronic devices. Moreover, it is also observed that the bandgap can be tuned by applying external strain and electric field, while the characteristic Dirac cone is maintained throughout. The application of an external electric field is found to be more effective in bandgap modulation. It leads to a linear change in the bandgap, with a bandgap value of 402 meV for 4 V nm −1 . The results obtained from our study indicate that Sn/BeO heterostructure can be a suitable material for the development of spintronic devices.

A highly selective formaldehyde (HCHO) gas sensor using a tin oxide nanoparticles−reduced graphene oxide (rGO−SnO 2 ) composite has been fabricated and investigated for room-temperature sensing. The rGO−SnO 2 composite is synthesized by cost-effective wet chemical method. The fabricated sensor exhibits remarkable sensing performance, including a higher response, a low detection limit of ≈33 ppb (theoretical), good selectivity, and long-term stability. Furthermore, the effects of humidity level and calcination temperature have also been investigated. The response and recovery times for 10 ppm HCHO vapor are found to be 35 and 10 s, respectively. The promising results in the lab-scale HCHO detection with pre-treated fish opens up avenues for the non-invasive detection of HCHO in food adulteration. The density functional theory study is in good agreement with the experimental results. The electronic charge density differences of the rGO−SnO 2 composite in the proximity of HCHO show significant variation. In addition, the sensing mechanism of the rGO−SnO 2 composite toward HCHO has also been discussed.