title: Nanochannel-directed growth of multi-segment nanowire heterojunctions of metallic Au(1-x)Ge(x) and semiconducting Ge.
abstract: We report on the synthesis of multi-segment nanowire (NW) junctions of Au(1-x)Ge(x) and Ge inside the nanochannels of porous anodic aluminum oxide template. The one-dimensional heterostructures are grown with a low-temperature chemical vapor deposition process, assisted by electrodeposited Au nanowires (AuNWs). The Au-catalyzed vapor-liquid-solid growth process occurs simultaneously in multiple locations along the nanochannel, which leads to multi-segment Au(1-x)Ge(x)/Ge heterojunctions. The structures of the as-grown hybrid NWs, analyzed by using transmission electron microscopy and energy-dispersive X-ray spectroscopy elemental mapping, show clear compositional modulation with variable modulation period and controllable junction numbers. Remarkably, both GeNW and Au(1-x)Ge(x)NW segments are single crystalline with abrupt interfaces and good crystallographic coherences. The electronic and transport properties of individual NW junctions are measured by using a multi-probe scanning tunneling microscope, which confirms the semiconducting nature of Ge segments and the metallic behavior of Au(1-x)Ge(x) segments, respectively. The high yield of multiple segment NW junctions of a metal-semiconductor can facilitate the applications in nanoelectronics and optoelectronics that harness multiple functionalities of heterointerfaces.
authors.affiliation: Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China.
authors.forename: Xiangdong
authors.initials: X
authors.lastname: Li
authors.forename: Guowen
authors.initials: G
authors.lastname: Meng
authors.forename: Shengyong
authors.initials: S
authors.lastname: Qin
authors.forename: Qiaoling
authors.initials: Q
authors.lastname: Xu
authors.forename: Zhaoqin
authors.initials: Z
authors.lastname: Chu
authors.forename: Xiaoguang
authors.initials: X
authors.lastname: Zhu
authors.forename: Mingguang
authors.initials: M
authors.lastname: Kong
authors.forename: An-Ping
authors.initials: AP
authors.lastname: Li
mesh_terms: D003460:Crystallization / Q000379:methods*; D005857:Germanium / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D008422:Materials Testing; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D012666:Semiconductors
chemical_list: D005857:Germanium; D006046:Gold