A simple method for preparing a TiO2-based back-gate controlled N-channel MSM–IGFET UV photodetector

Abstract

Atomic layer deposition (ALD) is used to grow a TiO₂ film on a SiO₂/Si substrate. A 50 μm N-channel, gate-regulated UV photodetector was fabricated by a simple process of air calcination and mask plating the electrode. The calcination process was found to improve the crystallinity of TiO₂, reduce the concentration of the majority of carriers, and increase their mobility (∼0.05 cm² V⁻¹ s⁻¹). The photoelectric performance of the as-prepared device is improved by about 200 times after calcination under the same test conditions. The as-prepared device has both gate voltage tunable properties of the insulated gate field effect transistor (IGFET) and a high gain (2–3 × 10⁴). At a gate voltage of 8 V and a drain voltage of 3 V, the external quantum efficiency of the device to 0.5 mW cm⁻² of 330 nm UV light is ∼2003%. The preparation of such a MSM–IGFET device will be helpful in reducing the device fabrication cost, optimizing the device performance, and promoting the application of photodetection.