Development of a UV photodetector using a Schottky diode and a transistor based on ZnO by spray pyrolysis

Abstract

High values of ultraviolet radiation expose in tropical and subtropical countries, presents a risk to public health, mainly on the possibility of skin cancer. The monitoring of UV radiation exposition by thin, flexible and printable circuits it's a fascinating proposal. This requires low cost materials that can be process by solution. The ZnO is a semiconductor that stands out in this respect. It has high mobility value and is promising for UV sensor applications because it has a band gap of 3,3 eV, that corresponds to the beginning of the UV light spectrum (320~400 nm). The use of the spray pyrolysis technique to obtain ZnO is interesting because allows it to be extracted from an organic precursor. This material can be used to develop a Schottky diode that can act as a good UV sensor. In addition, it can be also used to develop a transistor, an extremely important electronic component that its present in almost all of the electronic circuits. The integration of a Schottky diode and a thin film transistor forms a photodetector capable of "preprocessing" the signal, regulating the output voltage and selecting the intensity and wavelength to be detected. (AU)