Indium–Gallium–Zinc Oxide Schottky Diodes Operating across the Glass Transition of Stimuli‐Responsive Polymers

Abstract

Abstract Implementing stable electronic components on smart, soft materials can facilitate increasingly complex functionality in body‐worn and implanted devices for biomedical applications. The fabrication and characterization of indium–gallium–zinc oxide (IGZO)‐based Schottky diodes on a thiol–ene/acrylate shape memory polymer (SMP) that softens in response to physiological stimuli, including temperature and moisture, are presented. A platinum–IGZO Schottky junction is formed on the softening polymer assisted by ultraviolet‐ozone (UV‐O3) surface treatment. The effects of the UV‐O3 treatment conditions on the Schottky barrier properties are examined. The diode operation is evaluated in dry and wet conditions with varying temperatures up to 75 °C, revealing that the fabricated diodes preserve their performance even after the softening effect (i.e., an orders‐of‐magnitude modulus change) is induced in the polymer substrate. Additionally, high‐frequency diode operation up to 1 GHz is demonstrated for devices with an active area of 10 000 µm2 at 0 V bias. These devices can serve as building blocks for high‐frequency rectifying circuits and in more sophisticated arrangements toward applications in, for example, wireless bioelectronic implants.

Keywords

• indium–gallium–zinc oxide, IGZO
• Schottky diodes
• soft electronics
• softening polymers
• stimuli responsive materials