Pauporté Thierry, Lupan Oleg, Zhang Jie, Tugsuz Tugba, Ciofini Ilaria, Labat Frédéric, Viana Bruno
†Institut de Recherche de Chimie-Paris, CNRS-Chimie ParisTech-PSL, UMR8247, 11 rue Pierre et Marie Curie, 75005 Paris, France.
‡Department of Microelectronics and Biomedical Engineering, Technical University of Moldova, 168 Stefan cel Mare Boulevard, Chisinau MD-2004, Republic of Moldova.
ACS Appl Mater Interfaces. 2015 Jun 10;7(22):11871-80. doi: 10.1021/acsami.5b01496. Epub 2015 Jun 2.
Doping ZnO nanowires (NWs) by group IB elements is an important challenge for integrating nanostructures into functional devices with better and tuned performances. The growth of Ag-doped ZnO NWs by electrodeposition at 90 °C using a chloride bath and molecular oxygen precursor is reported. Ag acts as an electrocatalyst for the deposition and influences the nucleation and growth of the structures. The silver atomic concentration in the wires is controlled by the additive concentration in the deposition bath and a content up to 3.7 atomic % is reported. XRD analysis shows that the integration of silver enlarges the lattice parameters of ZnO. The optical measurements also show that the direct optical bandgap of ZnO is reduced by silver doping. The bandgap shift and lattice expansion are explained by first principle calculations using the density functional theory (DFT) on the silver impurity integration as an interstitial (Ag(i)) and as a substitute of zinc atom (Ag(Zn)) in the crystal lattice. They notably indicate that Ag(Zn) doping forms an impurity band because of Ag 4d and O 2p orbital interactions, shifting the Fermi level toward the valence band. At least, Ag-doped ZnO vertically aligned nanowire arrays have been epitaxially grown on GaN(001) substrate. The heterostructure has been inserted in a light emitting device. UV-blue light emission has been achieved with a low emission threshold of 5 V and a tunable red-shifted emission spectrum related to the bandgap reduction induced by silver doping of the ZnO emitter material.
通过IB族元素对氧化锌纳米线（NWs）进行掺杂，对于将纳米结构集成到性能更优且可调控的功能器件而言是一项重大挑战。本文报道了在90°C下使用氯化物浴和分子氧前驱体通过电沉积法生长银掺杂氧化锌纳米线的情况。银作为沉积的电催化剂，影响结构的成核和生长。纳米线中银原子浓度由沉积浴中的添加剂浓度控制，报道的含量高达3.7原子%。X射线衍射（XRD）分析表明，银的掺入增大了氧化锌的晶格参数。光学测量还表明，银掺杂降低了氧化锌的直接光学带隙。利用密度泛函理论（DFT）对银杂质在晶格中作为间隙原子（Ag(i)）和替代锌原子（Ag(Zn)）的整合进行第一性原理计算，解释了带隙移动和晶格膨胀现象。计算结果显著表明，由于Ag 4d和O 2p轨道相互作用，Ag(Zn)掺杂形成杂质带，使费米能级向价带移动。至少，银掺杂氧化锌垂直排列纳米线阵列已在GaN(001)衬底上外延生长。该异质结构已被插入发光器件中。实现了紫外-蓝光发射，发射阈值低至5 V，且发射光谱红移可调，这与氧化锌发射材料银掺杂引起的带隙减小有关。
