Band gap engineering and photoelectronic properties of novel pentagonal materials penta-XN₂ (X = Ni, Pt): a first principle calculations

Abstract Two-dimensional pentagonal materials as the next-generation nanoelectronic devices are promising candidates due to their interesting structures and novel electronic, mechanical, optical and other properties. Penta-NiN 2 , a newly synthesized material with pentagonal atomic arrangement under high pressure (ACS Nano 15 (2021), 13 539), has also sparked considerable interest. This study systematically investigates the effects of the biaxial strain on the electronic structure of monolayer penta-NiN 2 (penta-PtN 2 ). Furthermore, combining the non-equilibrium Green’s function approach, we research the optoelectronic and transport properties of penta-NiN 2 (PtN 2 ). The results indicate that biaxial strain can effectively modulate the bandgap of penta-NiN 2 (PtN 2 ), particularly achieving a semiconductor-to-metal transition under compressive strain. Moreover, tensile and compressive strains effectively enhance the optical characteristics of penta-NiN 2 (PtN 2 ) in visible light range. Under tensile and compressive strains, the absorption peak of penta-NiN 2 shows a red shift and a blue shift in visible region, respectively. The pin-junction photodiode of penta-NiN 2 (PtN 2 ) exhibit significant photocurrent under illumination. The strongest photocurrent is observed in penta-NiN 2 photodiodes under −3% compressive strain, showing the highest response to yellow light. Under the tensile stress of 7% and compressive stress of −3%, the photocurrent of the Penta-PtN 2 photodiode is enhanced in the yellow and green light regions. Additionally, applying compressive strain reduces the bandgap of penta-NiN 2 (PtN 2 ), significantly enhancing its transport properties and thereby inducing a switch effect in devices. In summary, our study demonstrates that penta-XN 2 (X = Ni, Pt) is a promising material in the fields of nanoelectronics and optoelectronic devices.