ZnO based surface acoustic wave ultraviolet photo sensor

Abstract

Ultraviolet (UV) sensor based on ZnO thin film surface acoustic wave (SAW) device is reported. ZnO films were grown using an RF magnetron sputtering technique. SAW devices were made using such ZnO films exhibiting a central frequency at ∼41.2 MHz. The SAW UV sensor was fabricated by depositing a 70 nm thin photoconducting ZnO overlayer on the fabricated SAW device. The SAW UV sensor was found to exhibit interesting photoresponse behavior to UV illumination, and a downshift in frequency of ∼45 kHz, and a change in insertion loss ∼1.1 dB were observed under UV illumination intensity of 19 mW/cm 2 . The changes in the frequency of operation and the insertion loss have been attributed to the acoustoelectric interaction between the photogenerated charge carriers and the potential associated with the acoustic waves. Results show the promise of ZnO for the fabrication of low cost wireless SAW UV sensors.

High-quality vertically aligned ZnO nanorods synthesized by microwave-assisted CBD with ZnO–PVA complex seed layer on Si substrates

“…Zinc oxide (ZnO), a wide bandgap (3.37 eV) semiconductor with a high exciton binding energy of 60 meV, and large internal piezoelectric coefficient, is a potentially significant and functional material for nanorod/nanowire structures [4]. ZnO nanorod/nanowire structures can be used as foundation blocks in a variety of applications such as short-wavelength nanolasers [5,6], field-effect transistors [7], nanosized gas sensors [8][9][10], nanoresonators, UV sensors [11][12][13], nanocantilevers [14], blue electroluminescent devices [15], high heterojunction area solar cells [16][17][18], and field emitters [19]. ZnO nanorods/nanowires can be grown using a variety of methods such as chemical vapor deposition (CVD), thermal evaporation [20,21], electrodeposition [22,23], catalyst-free combust-oxidized mesh (CFCOM) [24], oxidizing in air Zn metal films [25], and chemical bath deposition (CBD) [26][27][28].…”

Ultraviolet sensing based on nanostructured ZnO/Si surface acoustic wave devices

“…Where is the resonace frequency, ∆ is the frequency shift of SAW devices, and results listed in references [13], [14] and [21], the UV light sensitivities in this work are compatible, especailly for ZnO NRs, which has the largest sensitivity in Table 1.…”

“…ZnO has been deposited onto various piezoelecric materials for fabricating UV detectors based on SAW devices, such as ZnO/sapphire [12], ZnO/quartz [13], ZnO/LiNbO3 [14] and ZnO/LiTaO3 [15].…”

SAW UV sensors using ZnO nanorods grown on AlN/Si structures

“…ZnO has been widely used for ultraviolet (UV) detectors such as metal-semiconductor-metal phototransistors, photodiodes or surface acoustic wave (SAW)-based photodetectors. Among these devices, SAW devices have advantages which allow for remote wireless operation and a high potential in passive sensors [2][3][4][5].…”