Laser Thermal Treatment-Induced MgxZn1-xO Gradient Film and Photodetector with Solar-Blind UV Response

MgxZn1-xO is a ternary oxide semiconductor, which has an important application prospect in solar-blind UV detection fields. Herein, MgxZn1-xO gradient film is realized utilizing the sol-gel method and laser thermal treatment process. X-ray diffraction (XRD) pattern and absorption curve show that the gradient film has a single (002) crystal orientation and a single absorption edge. Field-emission scanning electron microscope and energy-dispersive spectroscopy characterization and finite-element analysis simulation prove that the laser thermal treatment temperature on the gradient film decreases from 1100 to 600 degrees C, corresponding to the Mg2+ component gradually increasing from 35% to 54% and the bandgap broadening from 3.75 to 5.08 eV. Metal-semiconductor-metal-structured photodetectors (PDs) are fabricated based on the gradient film. The high responsivity is attributed to the capture and the prolonged lifetime of photogenerated holes. Herein, an idea for the preparation of gradient film and the development of UVC and UVA multiband PDs is provided.