Oh Byeong-Yun, Han Jin-Woo, Seo Dae-Shik, Kim Kwang-Young, Baek Seong-Ho, Jang Hwan Soo, Kim Jae Hyun
Department of Electrical and Electronic Engineering, Yonsei University, 262 Seongsanno, Seodaemun-Gu, Seoul 120-749, Republic of Korea.
J Nanosci Nanotechnol. 2012 Jul;12(7):5330-5. doi: 10.1166/jnn.2012.6255.
We report the structural, electrical, and optical characteristics of Al-doped ZnO (ZnO:Al) films deposited on glass by atomic layer deposition (ALD) with various Al2O3 film contents for use as transparent electrodes. Unlike films fabricated by a sputtering method, the diffraction peak position of the films deposited by ALD progressively moved to a higher angle with increasing Al2O3 film content. This indicates that Zn sites were effectively replaced by Al, due to layer-by-layer growth mechanism of ALD process which is based on alternate self-limiting surface chemical reactions. By adjusting the Al2O3 film content, a ZnO:Al film with low electrical resistivity (9.84 x 10(-4) Omega cm) was obtained at an Al2O3 film content of 3.17%, where the Al concentration, carrier mobility, optical transmittance, and bandgap energy were 2.8 wt%, 11.20 cm2 V(-1) s(-1), 94.23%, and 3.6 eV, respectively. Moreover, the estimated figure of merit value of our best sample was 8.2 m7Omega(-1). These results suggest that ZnO:Al films deposited by ALD could be useful for electronic devices in which especially require 3-dimensional conformal deposition of the transparent electrode and surface passivation.
我们报告了通过原子层沉积（ALD）在玻璃上沉积的不同Al2O3薄膜含量的Al掺杂ZnO（ZnO:Al）薄膜用作透明电极时的结构、电学和光学特性。与通过溅射法制备的薄膜不同，ALD沉积的薄膜的衍射峰位置随着Al2O3薄膜含量的增加而逐渐向更高角度移动。这表明由于基于交替自限性表面化学反应的ALD工艺的逐层生长机制，Zn位点被Al有效取代。通过调整Al2O3薄膜含量，在Al2O3薄膜含量为3.17%时获得了低电阻率（9.84×10(-4)Ω·cm）的ZnO:Al薄膜，此时Al浓度、载流子迁移率、光学透过率和带隙能量分别为2.8 wt%、11.20 cm2 V(-1) s(-1)、94.23%和3.6 eV。此外，我们最佳样品的估计品质因数为8.2 mΩ(-1)。这些结果表明，通过ALD沉积的ZnO:Al薄膜可用于特别需要透明电极的三维共形沉积和表面钝化的电子器件。
