Abrupt Schottky Junctions in Al/Ge Nanowire Heterostructures
#MMPMID26052733
Kral S
; Zeiner C
; Stöger-Pollach M
; Bertagnolli E
; den Hertog MI
; Lopez-Haro M
; Robin E
; El Hajraoui K
; Lugstein A
Nano Lett
2015[Jul]; 15
(7
): 4783-7
PMID26052733
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In this Letter we report on the exploration of axial metal/semiconductor (Al/Ge)
nanowire heterostructures with abrupt interfaces. The formation process is
enabled by a thermal induced exchange reaction between the vapor-liquid-solid
grown Ge nanowire and Al contact pads due to the substantially different
diffusion behavior of Ge in Al and vice versa. Temperature-dependent I-V
measurements revealed the metallic properties of the crystalline Al nanowire
segments with a maximum current carrying capacity of about 0.8 MA/cm(2).
Transmission electron microscopy (TEM) characterization has confirmed both the
composition and crystalline nature of the pure Al nanowire segments. A very sharp
interface between the ?111? oriented Ge nanowire and the reacted Al part was
observed with a Schottky barrier height of 361 meV. To demonstrate the potential
of this approach, a monolithic Al/Ge/Al heterostructure was used to fabricate a
novel impact ionization device.
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