High-throughput investigation of a lead-free AlN-Based piezoelectric material, (Mg,Hf)xAl1-xN

Hung H. Nguyen, Hiroyuki Oguchi, Le Van Minh, Hiroki Kuwano

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18 Citations (Scopus)


We conducted a high-throughput investigation of the fundamental properties of (Mg,Hf)xAl1-xN thin films (0 < x < 0.24) aiming for developing high-performance AlN-based piezoelectric materials. For the high-throughput investigation, we prepared composition-gradient (Mg,Hf)xAl1-xN films grown on a Si(100) substrate at 600 °C by cosputtering AlN and MgHf targets. To measure the properties of the various compositions at different positions within a single sample, we used characterization techniques with spatial resolution. X-ray diffraction (XRD) with a beam spot diameter of 1.0 mm verified that Mg and Hf had substituted into the Al sites and caused an elongation of the c-axis of AlN from 5.00 Å for x = 0 to 5.11 Å for x = 0.24. In addition, the uniaxial crystal orientation and high crystallinity required for piezoelectric materials to be used as application devices were confirmed. The piezoelectric response microscope indicated that this c-axis elongation increased the piezoelectric coefficient almost linearly from 1.48 pm/V for x = 0 to 5.19 pm/V for x = 0.24. The dielectric constants of (Mg,Hf)xAl1-xN were investigated using parallel plate capacitor structures with -0.07 mm2 electrodes and showed a slight increase by substitution. These results verified that (Mg,Hf)xAl1-xN is a promising material for piezoelectric-based application devices, especially for vibrational energy harvesters.

Original languageEnglish
Pages (from-to)365-369
Number of pages5
JournalACS Combinatorial Science
Issue number6
Publication statusPublished - 2017 Jun 12


  • combinatorial approach
  • dielectric constant
  • Mg/Hf codoped AlN
  • piezoelectric coefficient
  • piezoelectric material


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