Design high performance field-effect, strain/gas sensors of novel 2D penta-like Pd2P2SeX (X= O, S, Te) pin-junction nanodevices: A study of transport properties

In the realm of modern nanodevices, attaining high-switching performance and fulfilling sensing detection functions in high-precision environments are of paramount importance. Two-dimensional (2D) Pd2P2SeX (X=O, S, Te) have excellent geometric, physical, and chemical characteristics, and can crystallize into orthogonal structures with indirect band gaps. Based on these fundamental properties, 2D Pd2P2SeX pin-junction devices were modeled via first principles to simulate field-effect transistors, strain sensors with high-switching ratios, and chemisorption-based gas sensors. The Pd2P2SeX pin-junction device exhibited significant gate-voltage control over current, with current changes over nearly three orders of magnitude for Pd2P2SeO. Moreover, the application of a biaxial strain could close the band gap of Pd2P2SeX and significantly enhance transport characteristics, leading to substantial switching effects in devices, such as a 1.44×108 switching ratio for Pd2P2SeS. The chemisorption of NO and NO2 produced interfacial electronic coupling that generated an impurity band crossing the Fermi level, thereby inducing a semiconducting to metallic transition. Pd2P2SeO- and Pd2P2SeS-based pin-junction devices exhibited 49.01 and 23.80 s recovery times, respectively, when detecting NO and NO2. Hence, they could be used as high-sensitivity and -selectivity gas sensors. Overall, 2D Pd2P2SeX materials have a vast potential for the development of low-dimensional electronic devices.