Schematic view of nanoneedle device: (a) scheme of the nanoneedle device; (b) equivalent circuit of the nanoneedle device for the reverse biased regimes and for the case of large gap between bulk silicon region and metal surface; and (c) equivalent circuit of the nanoneedle device for the forward biased regimes.
SEM image of silicon nanoneedles: (a) silicon nanoforest structure and (b) high magnification image of the Si nanoneedle tip.
Scheme of device fabrication: (1) initial Si substrates, (2A) RIE etching with PlasmaTerm-70 system, (3A) ICP etching with STS system, [(2B), (4A), and (5B)] metal contact deposition with CHA-600 -beam evaporator, and (3B) polymer spin-on deposition. [Please note that the Si wafer covered with Al film has been used as a carrier for the polymer film. The carrier wafer was separated and removed after bonding the polymer film to the nanoneedle surface at step (4B).] [(5A), (6A), and (4B)] Direct bonding at room temperature and bonding pressure and for metal and polymer films, respectively. [(5AA) and (6AA)] Structure obtained by dipping in de-ionized water. Inset shows schematically the interface of the bonded nanoforests.
Schematic view of cyclic voltammagrams of the investigated samples: (a) plate capacitor with Al–Al electrodes; (b) -type nanoneedle device; and (c) -type nanoneedle device.
(Color) Cyclic voltammagrams of the -type nanoneedle devices with and without de-ionized water electrolyte: PNNSAI—no water; PNNSA3—nanodevice without electrolyte, which was irradiated with IR light; PNNS WA2—with water; and PNNSWL1—with water and irradiated with IR light.
Energy band diagram for (a) -type and (b) -type silicon/electrolyte interface: is a band gap, is a work function for the couple, is a Si electron affinity, is a Helmholtz layer potential drop in case of negatively charged outer Helmholtz plane, and is a potential barrier.
Cyclic voltammagrams of nanoneedle devices: curves NNNSIM and NNNSIW2 are voltammagrams for the -type device with methanol and de-ionized water electrolytes, respectively; and curve NPNNSIW1 is for the device with de-ionized water electrolyte (please note that a hysteresis was only observed in samples with electrolyte).
Schematic view of ion current control device: (a) positively charged nanoneedle and (b) negatively charged nanoneedle. denotes ion atmosphere radius, is a value of interlayer gap, IM is electrolyte, NNSi denotes a silicon nanoneedle contact, and Al is metal contact.
Cyclic voltammagrams of the -type nanoneedle devices with silicone polymer electrolyte: TRTR5 curve was measured with integration time of , TRTR4 integration time was (for both curves, TRTR5 and TRTR4, the interlayer gap was ), and TRTR7 integration time was and the interlayer gap was .
Cyclic curves measured from the -type nanoneedle devices with silicone polymer electrolyte. Curves TRTR100RL and TRTR100LR were measured with meter at the frequency of . Curves TRTR500RL and TRTR500LR were measured at the frequency of . The scan was performed from for curves TRTR100RL and TRTR500RL, and from for curves TRTR100LR and TRTR500LR.
Article metrics loading...
Full text loading...