Dielectric Properties of Zinc Oxide Sensing Film With Nitrogen Doped in Capacitance Relative Humidity Sensor

A capacitance humidity sensor with a nitrogen-doped zinc oxide (N-doped ZnO) sensing film has been completed in this research. The N-doped ZnO material serves as a semiconductor sensing film with the Hall type of hole carriers (p-type). The carrier concentration and carrier mobility of p-type N-doped ZnO sensing films of capacitance humidity sensors without a polymer buffer layers are, respectively, 7.18 x 10(15) cm(-3) and 3.69 x 10(2) cm(2) /V.s. Besides, the carrier concentration and carrier mobility of p-type N-doped ZnO sensing films of capacitance humidity sensors with a polymer buffer layer are, respectively, 1.06 x 10(18) cm(3) and 3.34 x 10(2) cm(2)/V.s. The electrical resistivity of sensing films without and with the buffer layer reaches 4 x 10(2) and 8 x 10(2) Omega-cm, respectively. In the measurements of the moisture adsorption and desorption processes, the dielectric constant of the capacitance humidity sensor without a buffer layer exhibits a capacitance effect of about 460 nF/m. The sensitivity of 45 pFm(-1)/%RH for the relative humidity measurement of N-doped ZnO sensing films at the upper electrode terminal of the capacitance humidity sensor with a polymer buffer layer is also obtained.

Automated summary

In this research, a capacitance humidity sensor with a nitrogen-doped zinc oxide (N-doped ZnO) sensing film has been developed. The sensing film acts as a semiconductor with p-type hole carriers. The addition of a polymer buffer layer on the sensing film affects the carrier concentration and carrier mobility. The measurements demonstrate the capacitance effect and sensitivity of the sensor.