Transparent Conductive Oxide Nanocrystals Coated with Insulators by Atomic Layer Deposition

Thin films comprised of transparent conductive oxide (TCO) nanocrystals are attractive for a number of optoelectronic applications. However, it is often observed that the conductivity of such films is very low when they are in contact with air. It has recently been demonstrated, somewhat surprisingly, that filling in initially insulating films comprised of TCO nanocrystals with another insulator by atomic layer deposition (ALD) dramatically increases the conductivity by many orders of magnitude. This work aims to elucidate the mechanism by which the ALD coating increases conductivity. We examined the effect of removing two adsorbed oxygen species (physisorbed molecular water and chemisorbed hydroxide) on sheet resistance and compared this result to the results with thin films comprised of ZnO nanocrystals coated with Al2O3 and also HfO2 by ALD. Although both insulating infills decrease the sheet resistance and increase the stability of the films, there is a stark discrepancy between the two. From the in s...

[1]  E. Aydil,et al.  Nonequilibrium-Plasma-Synthesized ZnO Nanocrystals with Plasmon Resonance Tunable via Al Doping and Quantum Confinement. , 2015, Nano letters.

[2]  J. Shyue,et al.  Stable and High-Performance Flexible ZnO Thin-Film Transistors by Atomic Layer Deposition. , 2015, ACS applied materials & interfaces.

[3]  E. Aydil,et al.  High electron mobility in thin films formed via supersonic impact deposition of nanocrystals synthesized in nonthermal plasmas , 2014, Nature Communications.

[4]  N. Zhang,et al.  Colloidal Indium-Doped Zinc Oxide Nanocrystals with Tunable Work Function: Rational Synthesis and Optoelectronic Applications , 2014 .

[5]  Christopher B. Murray,et al.  Synthesis of N-Type Plasmonic Oxide Nanocrystals and the Optical and Electrical Characterization of their Transparent Conducting Films , 2014 .

[6]  V. Wood,et al.  High-Quality Transparent Electrodes Spin-Cast from Preformed Antimony-Doped Tin Oxide Nanocrystals for Thin Film Optoelectronics , 2013 .

[7]  Shouheng Sun,et al.  High-Temperature Solution-Phase Syntheses of Metal-Oxide Nanocrystals , 2013 .

[8]  Yongming Hu,et al.  Hydrogen Gas Sensors Based on Semiconductor Oxide Nanostructures , 2012, Sensors.

[9]  Raffaella Buonsanti,et al.  Tunable infrared absorption and visible transparency of colloidal aluminum-doped zinc oxide nanocrystals. , 2011, Nano letters.

[10]  A Paul Alivisatos,et al.  Localized surface plasmon resonances arising from free carriers in doped quantum dots. , 2011, Nature materials.

[11]  K. Poeppelmeier,et al.  Transparent Conducting Oxides in the ZnO-In2O3-SnO2 System , 2010 .

[12]  Ichiro Yamada,et al.  Competitive surface effects of oxygen and water on UV photoresponse of ZnO nanowires , 2009 .

[13]  M. Muhler,et al.  The identification of hydroxyl groups on ZnO nanoparticles by infrared spectroscopy. , 2008, Physical chemistry chemical physics : PCCP.

[14]  B. Park,et al.  Preparation and Optical Properties of Colloidal, Monodisperse, and Highly Crystalline ITO Nanoparticles , 2008 .

[15]  Taihong Wang,et al.  Rapid and ultrahigh ethanol sensing based on Au-coated ZnO nanorods , 2008, Nanotechnology.

[16]  Yunzhi Wang,et al.  In situ infrared spectroscopy of hafnium oxide growth on hydrogen-terminated silicon surfaces by atomic layer deposition , 2005 .

[17]  Sangsig Kim,et al.  Photoresponse of sol-gel-synthesized ZnO nanorods , 2004 .

[18]  Chenglu Lin,et al.  Fabrication and ethanol sensing characteristics of ZnO nanowire gas sensors , 2004 .

[19]  Steven M. George,et al.  Growth of ZnO/Al2O3 Alloy Films Using Atomic Layer Deposition Techniques , 2003 .

[20]  Y. Takahashi,et al.  Photoconductivity of Ultrathin Zinc Oxide Films , 1994 .

[21]  Isao Yasumoto.  Adsorption of water, ammonia, and carbon dioxide on zinc oxide at elevated temperatures , 1984 .

[22]  D. G. Thomas,et al.  Hydrogen as a Donor in Zinc Oxide , 1956, Halbleiter und Phosphore.