Strain engineering of Hf2CO2 MXene for enhanced transport and photoresponse in nanodevices

MXenes have emerged as promising semiconductor materials for applications in nanoelectronics and optoelectronics. In this study, Hf 2 CO 2 MXene was systematically investigated to elucidate its intrinsic material properties, quantum transport behavior, and photoelectric response mechanisms. The Hf 2 CO 2 monolayer was identified as a stable semiconductor with a bandgap of 1.57 eV. Notably, this bandgap was modulated under biaxial tensile strain, increasing to 1.83 eV under 4 % strain and to 1.94 eV under 8 % strain. This material is predicted to retain dynamic, thermal, and mechanical stability throughout strain application. Additionally, strain engineering significantly enhanced device performance: the current density of the p–n junction diode reached 47 mA/mm, while the p–i–n junction field-effect transistor achieved a maximum current density of 1000 mA/mm at a gate voltage of − 4 V under 8 % strain. In terms of the photoresponse, Hf 2 CO 2 exhibited distinct absorption peaks in the green–blue and ultraviolet regions. Under strain modulation, the intrinsic photocurrent density of the phototransistor reached 1.2 mA/mm 2 , highlighting its potential for broadband photodetection and photovoltaic applications.