Doped Hf0.5Zr0.5O2 for high efficiency integrated supercapacitors

Applications for integrated energy storage and pulse-power devices may have found opportunities in the emergence of the ferroelectric hafnium-zirconium oxide thin film system. To explore the boundaries of this material thin film system, 10 nm thick binary Hf0.5Zr0.5O2 (HZO) thin films are doped with Al or Si (Al or Si-doped HZO). The added dopants provide a distinct shift in behavior from ferroelectric to antiferroelectric characteristics. Si-doped Hf0.5Zr0.5O2 thin films exhibited a larger than 50 J/cm3 energy storage density with an efficiency of over 80%. The Si-doped Hf0.5Zr0.5O2 thin films were cycled 109 times up to 125 °C and maintained a robust 35 J/cm3 energy storage density and greater than 80% efficiency. Al-doped Hf0.5Zr0.5O2 thin films exhibited a larger switching field, leading to a smaller energy storage density and less robust cycling properties than Si-doped Hf0.5Zr0.5O2.