Growth of doped silicon nanowires by pulsed laser deposition and their analysis by electron beam induced current imaging

Abstract

Doped silicon nanowires (NWs) were epitaxially grown on silicon substrates by pulsed laser deposition following a vapour-liquid-solid process, in which dopants together with silicon atoms were introduced into the gas phase by laser ablation of lightly and highly doped silicon target material. p-n or p(++)-p junctions located at the NW-silicon substrate interfaces were thus realized. To detect these junctions and visualize them the electron beam induced current technique and two-point probe current-voltage measurements were used, based on nanoprobing individual silicon NWs in a scanning electron microscope. Successful silicon NW doping by pulsed laser deposition of doped target material could experimentally be demonstrated. This doping strategy compared to the commonly used doping from the gas phase during chemical vapour deposition is evaluated essentially with a view to potentially overcoming the limitations of chemical vapour deposition doping, which shows doping inhomogeneities between the top and bottom of the NW as well as between the core and shell of NWs and structural lattice defects, especially when high doping levels are envisaged. The pulsed laser deposition doping technique yields homogeneously doped NWs and the doping level can be controlled by the choice of the target material. As a further benefit, this doping procedure does not require the use of poisonous gases and may be applied to grow not only silicon NWs but also other kinds of doped semiconductor NWs, e.g. group III nitrides or arsenides.

Overview and status of bottom-up silicon nanowire electronics

“…NWs with crystalline Si cores as thin as 5 nm have been achieved via a modified LA process [32]. Remarkably, doping of Si NWs via LA has been recently achieved by ablating doped Si targets [33]. However, the need for complex, expensive equipment has so far limited this technique utilisation.…”

“…An interesting example of the first approach is the crossbar architecture [132,33]. In this structure, arrays of parallel Si NWs are overlapped in crossed geometry and form active devices at each intersection.…”

Obtaining and doping of InAs-QD/GaAs(001) nanostructures by ion beam sputtering

“…Besides the mentioned methods, classic growth methods such as liquid phase epitaxy [10], laser beam sputtering [11], electron beam sputtering [12] and ion beam sputtering [13] are being actively adapted for the growth of nanomaterials with quantum dots (QDs).…”

Morphology and Optical Investigations of InAs-QD/GaAs Heterostructures Obtained by Ion-Beam Sputtering

“…Besides these ones, other classical methods are being actively employed to produce nanostructured materials with quantum dots. Among them are liquid phase epitaxy [7], pulsed-laser deposition [8], electron beam sputtering [9], and ion-beam sputtering [10].…”