Institute for Microelectronics and Microsystems-Unit of Lecce, National Research Council (IMM-CNR), Via Monteroni, I-73100 Lecce, Italy.
Nanotechnology. 2012 Nov 23;23(46):465701. doi: 10.1088/0957-4484/23/46/465701. Epub 2012 Oct 23.
Conductivity and photoconductivity properties of individual GaAs/AlGaAs core-shell nanowires (NWs) are reported. The NWs were grown by Au-assisted metalorganic vapor phase epitaxy, and then dispersed on a substrate where electrical contacts were defined on the individual NWs by electron beam induced deposition. Under dark conditions, the carrier transport along the NW is found to be limited by Schottky contacts, and influenced by the presence of an oxide layer. Nonetheless, under illumination, the GaAs/AlGaAs core-shell NW shows a significant photocurrent, much higher than the bare GaAs NW. The spatial dependence of the photocurrent within the single core-shell NW, evaluated by a mapping technique, confirms the blocking behavior of the contacts. Moreover, local spectral measurements were performed which allow one to discriminate the contribution of carriers photogenerated in the core and in the shell.
本文报道了单个 GaAs/AlGaAs 核壳纳米线（NWs）的电导率和光电导特性。NWs 通过 Au 辅助的金属有机气相外延生长，并随后分散在基底上，通过电子束诱导沉积在各个 NW 上定义了电接触。在黑暗条件下，沿 NW 的载流子输运被发现受到肖特基接触的限制，并受到氧化物层的存在的影响。然而，在光照下，GaAs/AlGaAs 核壳 NW 表现出显著的光电流，远高于裸露的 GaAs NW。通过映射技术评估的单个核壳 NW 内光电流的空间依赖性，证实了接触的阻断行为。此外，还进行了局部光谱测量，允许区分在核和壳中产生的载流子的贡献。
