Fabrication of a ZnO Pyroelectric Sensor

Abstract

This paper proposes a two-step radio frequency (RF) sputtering process to form a ZnO film for pyroelectric sensors. It is shown that the two-step sputtering process with a lower power step followed by a higher power step can significantly improve the voltage responsivity of the ZnO pyroelectric sensor. The improvement is attributed mainly to the formation of ZnO film with a strongly preferred orientation towards the c-axis. Furthermore, a nickel film deposited onto the uncovered parts of the ZnO film can effectively improve the voltage responsivity at higher modulating frequencies since the nickel film can enhance the incident energy absorption of the ZnO layer.

Electrode layout of ZnO pyroelectric sensors

“…The most densely packed and thermodynamically favorable growth orientation in a ZnO wurtzite structure is the one with the c-axis perpendicular to a substrate. ZnO films, with the c-axis normal to the substrate, are preferred in many applications, such as ZnO pyroelectric devices [4,6] and film bulk acoustic resonators [7]. The pyroelectricity of ZnO is attributable to non-centro-symmetrical crystals and has a specific polar axis along the direction of spontaneous polarization [1,2].…”

“…ZnO films are usually deposited by RF sputtering. The properties of ZnO are affected by sputtering conditions such as the composition of mixed process gases, working pressure, substrate temperature, radio frequency (RF) power, the gap between the target and substrate, and the postannealing temperature [6,8].…”

The Optimization of the Thermal Response on the ZnO Flexible Pyroelectric Film Temperature Sensor

“…Pyroelectric sensors can be fabricated using a variety of techniques, including simultaneous RF and DC magnetron sputtering [1], metal organic chemical vapor deposition (MOCVD) [2], electron cyclotron resonance plasma sputtering and metal-organic decomposition [3], sol-gel processing [4], spray pyrolysis [5], aerosol deposition [6], and full inkjet printing [7], [8].…”

Synthesis and Characterization of ZnO Nanoparticles using Effective of Co Doped

“…These properties makes ZnO attractive in places where high hygiene it´s necessary [5]. Therefore, several methods were used to prepare ZnO nanoparticles such as: radio frequency (RF) sputtering process [6], CVD methods [7], pulsed laser deposition [8], spray pyrolisis [9], atomic layer deposition [10], chemical bath deposition [11] or electrodeposition [12]. In sol-gel technique, needs expensive precursors such as alkoxide or organometallic compounds.…”