Current−Voltage Characteristics of in Situ Graphitization of Hydrocarbon Coated on ZnSe Nanowire

Abstract

Current−voltage characteristics of hydrocarbon coated on ZnSe nanowire annealed by current-induced Joule heating have been studied via an in situ transmission electron microscope (TEM) technique. The major feature of the measured current−voltage curves is the presence of negative conductance due to a remarkable drop of current at the early stage of the graphitization which decreases the density of the band tail states resulting from hydrogen that escaped from various C-Hn clusters and the sp3 and sp2 coordinated carbon networks. At the later stage of graphitization, the current began to increase rapidly due to sp3 coordination transformation into sp2 coordination, which effectively narrowed the band gap. Finally, a linear relationship between the current and voltage appeared as a result of a phase transition from the amorphous hydrocarbon to graphite, leading to the semiconductor to conductor transition. The details revealed in the measured current−voltage curve strongly suggest that the electrical property of the hydrocarbon deposition may be optimized by intentional arrangement with current-induced Joule heating.

Fabrication of nanoporous carbon by electrical transformation of amorphous carbon nanospheres

“…The hydrogen in such amorphous carbon and DLC materials is typically partly bonded to carbon, the rest being in the form of molecular hydrogen inserted in the network [35]. Although not directly measurable, it is likely that the Joule heating initiates significant outflow of hydrogen from the nanospheres since the C-H bond is relatively easy to break [36]. This loss of hydrogen is consistent with the significant volume loss in the nanospheres observed in situ during their transformation.…”

“…In both these cases the carbon was doped with metals known to catalyse graphitization [40,41]. In other recent works amorphous carbon thin films have graphitized due to nanoscale frictional heating [42], and Joule heating initiated graphitization in the absence of catalysts has been observed in the TEM for amorphous carbon deposited on nano-objects such as ZnSe nanowires [36], Au nanowires [32], Si/SiO 2 nanochains [43] and CNTs [34,44].…”

Crystal orientation-dependent tensile mechanical behavior and deformation mechanisms of zinc-blende ZnSe nanowires

“…light-emitting diodes, nanosensors, nanoactuators, nanoresonators, and magnetic information storage [27][28][29][30][31][32][33][34][35][36][37] . However, despite considerable effort to assess the electronic, thermal, and optical characteristics of zinc-blende ZnSe NWs, both in theory 23,24,26,38,39 and in experiments [40][41][42][43][44][45][46] , to the best of our knowledge, there is no study on their mechanical properties. In particular, the tensile deformation mechanisms for different crystal orientations have not been reported in the literature.…”

Elimination of the Schottky Barrier at an Au-ZnSe Nanowire Nanocontact via in Situ Joule Heating

“…The Joule effect due to a high current density in the NWs with a very small diameter can heat the tiny mass up to a temperature as high as the melting point of the NW and has been used to study in situ recrystallization of nanocrystalline Si microwires, [9] transformation of a SiC NW and a Mo 6 S 3 I 6 NW into a carbon nanotube (CNT) and a Mo NW, respectively, via thermal decomposition, [10,11] CNT produced by crystallization of amorphous hydrocarbon and secondary nucleation on the existing CdTe NW due to the Joule heating-induced surface decomposition. [12,13] The electrical conductance of the resultant NWs and CNTs was significantly improved due to the transformation from semiconductor to conductor or refinement of crystal quality. In addition, the interfacial chemical reaction at the ZnSe NW-Au nanocontact caused by in situ Joule heating has also been conducted within TEM and welding of ZnSe NW to Au electrode and between the Pt NW were achieved.…”