Fabrication of field-effect transistors and functional nanogenerators using hydrothermally grown ZnO nanowires

RSC Advances ◽  
2015 ◽  
Vol 5 (86) ◽  
pp. 69925-69931 ◽  
Author(s):  
C. Opoku ◽  
A. S. Dahiya ◽  
F. Cayrel ◽  
G. Poulin-Vittrant ◽  
D. Alquier ◽  
...  
Keyword(s):  
Thermal Annealing ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Hydrothermal Process ◽  
Zno Nanowires ◽  
Zno Nanowire ◽  
Single Crystalline ◽  
Piezoelectric Nanogenerators

We demonstrate single crystalline ZnO nanowire (NW) production using hydrothermal process. Single NW field-effect transistors (FETs) and functional piezoelectric nanogenerators (NGs) are demonstrated by thermal annealing of the NWs in air at ~450 °C.

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

2011 ◽  
Vol 2011 ◽  
pp. 1-16 ◽  
Author(s):  
Jianshi Tang ◽  
Chiu-Yen Wang ◽  
Faxian Xiu ◽  
Yi Zhou ◽  
Lih-Juann Chen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermal Annealing ◽  
Rapid Thermal Annealing ◽  
Field Effect ◽  
High Performance ◽  
Lattice Mismatch ◽  
Field Effect Transistors ◽  
Single Crystalline ◽  
Nanowire Transistors ◽  
Nanowire Heterostructures

We reviewed the formation of Ge nanowire heterostructure and its field-effect characteristics by a controlled reaction between a single-crystalline Ge nanowire and Ni contact pads using a facile rapid thermal annealing process. Scanning electron microscopy and transmission electron microscopy demonstrated a wide temperature range of 400~500°C to convert the Ge nanowire to a single-crystalline Ni2Ge/Ge/Ni2Ge nanowire heterostructure with atomically sharp interfaces. More importantly, we studied the effect of oxide confinement during the formation of nickel germanides in a Ge nanowire. In contrast to the formation of Ni2Ge/Ge/Ni2Ge nanowire heterostructures, a segment of high-quality epitaxial NiGe was formed between Ni2Ge with the confinement of Al2O3during annealing. A twisted epitaxial growth mode was observed in both two Ge nanowire heterostructures to accommodate the large lattice mismatch in the NixGe/Ge interface. Moreover, we have demonstrated field-effect transistors using the nickel germanide regions as source/drain contacts to the Ge nanowire channel. Our Ge nanowire transistors have shown a high-performancep-type behavior with a high on/off ratio of 105and a field-effect hole mobility of 210 cm2/Vs, which showed a significant improvement compared with that from unreacted Ge nanowire transistors.

scholarly journals ZnO nanowires and their application in field-effect transistors

2021 ◽  
Author(s):  
◽  
Conor Patrick Burke-Govey
Keyword(s):  
Electron Beam ◽  
High Temperature ◽  
Field Dependence ◽  
Threshold Voltage ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Zno Nanowires ◽  
High Temperature Annealing ◽  
Zno Nanowire ◽  
Threshold Voltages

<p>ZnO nanowires have shown great promise as a semiconducting material for a variety of different electronic applications at the nanoscale, and can be easily synthesised at low temperatures using the hydrothermal growth method. However, efforts to reliably produce field-effect transistors (FETs) using ZnO nanowires have been hampered by excessive charge carriers, requiring high temperature annealing (≥400°C) at the expense of the low-temperature synthesis before field dependence is achieved. This thesis presents hydrothermally synthesised ZnO nanowires which can effectively be used as FETs in dry and liquid environments without requiring any annealing or post-growth processing.  The role of polyethylenimine (PEI) in the hydrothermal growth of vertical ZnO nanowires is thoroughly investigated. PEI is a polymer used to increase the aspect ratio of ZnO nanowires, but the molecular weight of the polymer and interactions with other growth precursors are often overlooked. Using 4 mM of PEI(MW = 1300 g/mol) results in hierarchical nanowires, consisting of large primary nanowires which abruptly terminate in thinner secondary nanowires. The secondary nanowires, with lengths of up to 10 m and diameters below 50 nm, are synthesised during a PEI-mediated secondary growth phase, where Zn-PEI complexes continue to provide Zn²⁺ ions after the bulk of the precursors have been exhausted.  The PEI-mediated synthesis of hierarchical nanowires is used to fabricate FETs by laterally growing intersecting networks of nanowires from spaced pairs of ZnO/Ti films, which have been patterned on SiO₂/Si device substrates. All of these FETs show marked field dependence between VG = -10 V to 10 V, despite being used without annealing. Typical on-off ratios are between 10³ - 10⁵, with threshold voltages between -7.5 V to 5 V. This is a significant result, as the majority of ZnO nanowire FETs reported in the literature require high temperature annealing. Persistent photoconductivity measurements indicate that surface states on the nanowires contribute to the intrinsic field dependence of the devices.  Hierarchical nanowires are also synthesised by modular primary and secondary hydrothermal growths. FETs fabricated using these hierarchical nanowires show less field dependence than PEI-mediated hierarchical nanowires, with limited function ality when used in air. The best FET measured in air operates with an on-off ratio of 10⁴ and a threshold voltage of ~ 0 V. Devices which are field-independent in air can be reliably gated by measuring the FETs in a wet environment, using de-ionised water as a dielectric. A back-gated wet FET operates with an on-off ratio of 105 and a threshold voltage of ~ 8 V. Top-gated wet FETs operate with on-off ratios within 103 - 104, and threshold voltages within 0.4 - 0.9 V. These devices also have significantly low subthreshold swings, on the order of 80 mV/decade.  FETs are fabricated by contacting individual ZnO nanowires using electron-beam lithography, although only one vertical ZnO nanowire shows field dependence, with an on-off ratio of 10⁴ and a threshold voltage of -7 V. A PEI-mediated hierarchical nanowire is also contacted and shows field dependence, with an on-off ratio of 10² and a threshold voltage of -6 V. The poor on-off ratio is caused by high leakage currents of the device. The contacted nanowires undergo dissolution over time, disappearing from the substrates after 8 months, and also exhibit a conducting-to-insulating transition over 48 hours. This transition can be temporarily reversed by exposure to an electron beam. Neither of these effects are reported in the literature, and their causes are speculated on.  Finally, the thesis concludes with proposals for future work to further the advances made here.</p>

Comparison Between the Electrical Properties of ZnO Nanowires Based Field Effect Transistors Fabricated by Back- and Top-Gate Approaches

2008 ◽  
Vol 8 (11) ◽  
pp. 6010-6016 ◽  
Author(s):  
Y. K. Park ◽  
Ahmad Umar ◽  
S. H. Kim ◽  
J.-H. Kim ◽  
E. W. Lee ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Electron Beam Lithography ◽  
Field Effect ◽  
Thermal Evaporation ◽  
Field Effect Transistors ◽  
Zinc Powder ◽  
Zno Nanowires ◽  
Zno Nanowire ◽  
Back Gate ◽  
Source Materials

Large-quality, well-crystallized growth of ZnO nanowires was done via non-catalytic thermal evaporation process on silicon substrate only by using metallic zinc powder and oxygen as source materials for zinc and oxygen, respectively. The electrical properties of the as-grown ZnO nanowires were examined by fabricating a single nanowire based FETs which were fabricated via two approaches, i.e., back- and top-gate approaches by using electron beam lithography (EBL) and photolithography processes. ZnO FETs electrical properties were characterized by IDS–VDS and IDS–VGS measurement. The fabricated single ZnO nanowire based FETs by back- and top-gate approaches exhibited field effect mobilities of ∼4.25 and ∼12.76 cm2/Vs, respectively. Moreover, the carrier concentrations for the fabricated back- and top-gate FETs were ∼1.6 × 1017 and ∼1.37 × 1018 cm−3, respectively. From our studies it was observed that the fabricated top-gate FETs exhibited higher and good electrical properties as compared to ZnO nanowire FETs fabricated using back-gate approaches.

scholarly journals ZnO nanowires and their application in field-effect transistors

2021 ◽  
Author(s):  
◽  
Conor Patrick Burke-Govey
Keyword(s):  
Electron Beam ◽  
High Temperature ◽  
Field Dependence ◽  
Threshold Voltage ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Zno Nanowires ◽  
High Temperature Annealing ◽  
Zno Nanowire ◽  
Threshold Voltages

<p>ZnO nanowires have shown great promise as a semiconducting material for a variety of different electronic applications at the nanoscale, and can be easily synthesised at low temperatures using the hydrothermal growth method. However, efforts to reliably produce field-effect transistors (FETs) using ZnO nanowires have been hampered by excessive charge carriers, requiring high temperature annealing (≥400°C) at the expense of the low-temperature synthesis before field dependence is achieved. This thesis presents hydrothermally synthesised ZnO nanowires which can effectively be used as FETs in dry and liquid environments without requiring any annealing or post-growth processing.  The role of polyethylenimine (PEI) in the hydrothermal growth of vertical ZnO nanowires is thoroughly investigated. PEI is a polymer used to increase the aspect ratio of ZnO nanowires, but the molecular weight of the polymer and interactions with other growth precursors are often overlooked. Using 4 mM of PEI(MW = 1300 g/mol) results in hierarchical nanowires, consisting of large primary nanowires which abruptly terminate in thinner secondary nanowires. The secondary nanowires, with lengths of up to 10 m and diameters below 50 nm, are synthesised during a PEI-mediated secondary growth phase, where Zn-PEI complexes continue to provide Zn²⁺ ions after the bulk of the precursors have been exhausted.  The PEI-mediated synthesis of hierarchical nanowires is used to fabricate FETs by laterally growing intersecting networks of nanowires from spaced pairs of ZnO/Ti films, which have been patterned on SiO₂/Si device substrates. All of these FETs show marked field dependence between VG = -10 V to 10 V, despite being used without annealing. Typical on-off ratios are between 10³ - 10⁵, with threshold voltages between -7.5 V to 5 V. This is a significant result, as the majority of ZnO nanowire FETs reported in the literature require high temperature annealing. Persistent photoconductivity measurements indicate that surface states on the nanowires contribute to the intrinsic field dependence of the devices.  Hierarchical nanowires are also synthesised by modular primary and secondary hydrothermal growths. FETs fabricated using these hierarchical nanowires show less field dependence than PEI-mediated hierarchical nanowires, with limited function ality when used in air. The best FET measured in air operates with an on-off ratio of 10⁴ and a threshold voltage of ~ 0 V. Devices which are field-independent in air can be reliably gated by measuring the FETs in a wet environment, using de-ionised water as a dielectric. A back-gated wet FET operates with an on-off ratio of 105 and a threshold voltage of ~ 8 V. Top-gated wet FETs operate with on-off ratios within 103 - 104, and threshold voltages within 0.4 - 0.9 V. These devices also have significantly low subthreshold swings, on the order of 80 mV/decade.  FETs are fabricated by contacting individual ZnO nanowires using electron-beam lithography, although only one vertical ZnO nanowire shows field dependence, with an on-off ratio of 10⁴ and a threshold voltage of -7 V. A PEI-mediated hierarchical nanowire is also contacted and shows field dependence, with an on-off ratio of 10² and a threshold voltage of -6 V. The poor on-off ratio is caused by high leakage currents of the device. The contacted nanowires undergo dissolution over time, disappearing from the substrates after 8 months, and also exhibit a conducting-to-insulating transition over 48 hours. This transition can be temporarily reversed by exposure to an electron beam. Neither of these effects are reported in the literature, and their causes are speculated on.  Finally, the thesis concludes with proposals for future work to further the advances made here.</p>

Degradation of ZnO nanowire devices under the ambient condition

2008 ◽  
Vol 1080 ◽  
Author(s):  
Dong-Wook Kim ◽  
Soo-Han Choi ◽  
Hyun-Jin Ji ◽  
Sang Woo Kim ◽  
Seung Eon Moon ◽  
...  
Keyword(s):  
Electron Beam ◽  
Electrical Properties ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Ambient Condition ◽  
Zno Nanowires ◽  
Electrical Characteristics ◽  
Zno Nanowire ◽  
Defect States ◽  
Oxide Nanowires

ABSTRACTField effect transistors(FETs) made of ZnO nanowires are very sensitive to the gas environment, so that the passivation can be a good way to get reliable nanowire FETs with longer lifetime and the better mobility. The studies on the passivation effects with the positive electron-beam resist was investigated by selectively covering the part of nanowire devices between the electrodes. Reproducible electrical characteristics were recorded, reflecting the stable electrical properties by the passivation which deters the degradation of a device. Considering the defect states of oxide nanowires dominate the charge states, the pre-state just before the passivation process will be crucial to understand the reproducible and controllable device characteristics of nanowire devices.

Electron irradiation effect on the Schottky gate of ZnO nanowires-based field effect transistors

2011 ◽  
Vol 6 (6) ◽  
pp. 437 ◽  
Author(s):  
Qi Zhang ◽  
Junjie Qi ◽  
Yunhua Huang ◽  
Xin Li ◽  
Yue Zhang
Keyword(s):  
Electron Irradiation ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Zno Nanowires ◽  
Irradiation Effect

scholarly journals Electrical and optical properties of single As-doped ZnO nanowire field effect transistors

2009 ◽  
Vol 58 (6) ◽  
pp. 4156
Author(s):  
Zhang Jun-Yan ◽  
Deng Tian-Song ◽  
Shen Xin ◽  
Zhu Kong-Tao ◽  
Zhang Qi-Feng ◽  
...  
Keyword(s):  
Optical Properties ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Zno Nanowire ◽  
Electrical And Optical Properties ◽  
Doped Zno

Organic single crystalline micro- and nanowires field-effect transistors of a tetrathiafulvalene (TTF) derivative with strong π–π orbits and S⋯S interactions

2011 ◽  
Vol 161 (1-2) ◽  
pp. 136-142 ◽  
Author(s):  
Hui Jiang ◽  
Xianjin Yang ◽  
Erjing Wang ◽  
Yanyan Fu ◽  
Yaling Liu ◽  
...  
Keyword(s):  
Field Effect ◽  
Field Effect Transistors ◽  
Single Crystalline
Sign in / Sign up

Export Citation Format

Share Document