Linear-source ultrasonic spray chemical vapor deposition method for fabrication of ZnMgO films and ultraviolet photodetectors

A linear-source ultrasonic spray chemical vapor deposition method has been developed and applied to fabricate ZnMgO ternary alloy thin films on glass substrates. A water solution of zinc acetate and magnesium acetate was ultrasonically atomized to form aerosol particles of water containing the sources, and then they were supplied onto the heated substrate by a nitrogen carrier gas through a nozzle with a linear aperture to form ZnMgO films. The source concentration ratios in the water solution successfully controlled the solid composition and hence raised the band gap of ZnMgO up to 3.75 eV, keeping the optical transmission higher than 90% for the visible-light region. An UV photodetector fabricated using the ZnMgO film showed the photoresponsivity to be as high as a few A/W, suggesting that this simple and cost-effective technique is promising for fabricating ZnMgO films for various applications.