Formation and Device Application of Ge Nanowire Heterostructures via Rapid Thermal Annealing

Figure 5

Formation of Ni_xGe/Ge/Ni_xGe heterostructure with the Al₂O₃ confinement. (a) Schematic illustration of an Al₂O₃ conformal capping on the Ge nanowire device by ALD. (b) SEM image of the as-fabricated Ge nanowire device with EBL-defined Ni electrodes. (c) SEM image of the Ge nanowire device after a conformal capping of 20 nm thick Al₂O₃. (d) SEM image of the Ni_xGe/Ge/Ni_xGe heterostructure after RTA at 450°C for 20 s in which the length of the Ge region was easily controlled to be several hundred nanometers. The arrows indicate the growth tip of the Ni_xGe nanowire. (e) Schematic illustration showing the formation of Ni_xGe/Ge/Ni_xGe nanowire heterostructure with the Al₂O₃ confinement. The red line indicates the position chosen for FIB to study the cross-sectional structure in Figure 6. Reproduced from [14].

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