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Direct formation of gold nanoparticles on substrates using a novel ZnO sacrificial templated-growth hydrothermal approach and their properties in organic memory device.

Goh LP, Razak KA, Ridhuan NS, Cheong KY, Ooi PC, Aw KC - Nanoscale Res Lett (2012)

Bottom Line: Well-distributed and controllable AuNP sizes were successfully grown directly on the substrate, as observed using a field emission scanning electron microscope followed by an elemental analysis study.In this study, the AuNPs were charge-trapped sites and showed excellent memory effects when embedded in PMSSQ.Optimum memory properties of PMMSQ-embedded AuNPs were obtained for AuNPs synthesized on a seeded ZnO template annealed at 300°C, with 54 electrons trapped per AuNP and excellent current-voltage response between an erased and programmed device.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, Nibong Tebal, Penang 14300, Malaysia. khairunisak@eng.usm.my.

ABSTRACT
This study describes a novel fabrication technique to grow gold nanoparticles (AuNPs) directly on seeded ZnO sacrificial template/polymethylsilsesquioxanes (PMSSQ)/Si using low-temperature hydrothermal reaction at 80°C for 4 h. The effect of non-annealing and various annealing temperatures, 200°C, 300°C, and 400°C, of the ZnO-seeded template on AuNP size and distribution was systematically studied. Another PMMSQ layer was spin-coated on AuNPs to study the memory properties of organic insulator-embedded AuNPs. Well-distributed and controllable AuNP sizes were successfully grown directly on the substrate, as observed using a field emission scanning electron microscope followed by an elemental analysis study. A phase analysis study confirmed that the ZnO sacrificial template was eliminated during the hydrothermal reaction. The AuNP formation mechanism using this hydrothermal reaction approach was proposed. In this study, the AuNPs were charge-trapped sites and showed excellent memory effects when embedded in PMSSQ. Optimum memory properties of PMMSQ-embedded AuNPs were obtained for AuNPs synthesized on a seeded ZnO template annealed at 300°C, with 54 electrons trapped per AuNP and excellent current-voltage response between an erased and programmed device.

No MeSH data available.


Process flow for sacrificial templated-growth hydrothermal reaction of AuNPs embedded in the PMMSQ memory device. (a) PMMSQ/n-Si, (b) deposited ZnO layer, (c) thermal oxidation of ZnO layer to form ZnO seeds, (d) AuNPs formed on PMMSQ/n-Si, (e) another PMMSQ layer was deposited on the AuNPs, and (f) desired memory device structure with Al as top and bottom electrodes.
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Figure 1: Process flow for sacrificial templated-growth hydrothermal reaction of AuNPs embedded in the PMMSQ memory device. (a) PMMSQ/n-Si, (b) deposited ZnO layer, (c) thermal oxidation of ZnO layer to form ZnO seeds, (d) AuNPs formed on PMMSQ/n-Si, (e) another PMMSQ layer was deposited on the AuNPs, and (f) desired memory device structure with Al as top and bottom electrodes.

Mentions: A n-type (100) silicon wafer was cut into small pieces (dimension of 1 × 1 cm) and used as substrates. The silicon substrates were cleaned using a standard RCA cleaning process to remove the organic and inorganic contaminants from the surface. A polymethylsilsequioxane (PMSSQ) layer was deposited at 2,000 rpm for 100 s on the cleaned substrates to achieve 350-nm dielectric layers. Thereafter, the samples were cured in an oven at 160°C for 1 h (Figure 1a). A 200-nm-thick ZnO thin film was then deposited on each substrate using radio-frequency magnetron sputtering at 200 W (Figure 1b).The samples were annealed at different temperatures: 200°C, 300°C, and 400°C, with a ramp rate and soaking time of 5°C/min and 10 min, respectively, to observe the seed layer effects on AuNP formation (Figure 1c). Thereafter, the AuNPs were grown on the ZnO seed template using a sacrificial low-temperature hydrothermal approach. The ZnO-seeded samples were subjected to a hydrothermal reaction in a preheated oven at 80°C for 4 h. The hydrothermal bath contained 0.1 M zinc nitrate tetrahydrate (Zn(NO3)2·4H2O), 0.1 M hexamethylenetetramine (C6H12N4), 0.01 M gold(III) chloride trihydrate (AuCl4.3H2O), and 10 mL acetic acid. After hydrothermal reaction, the samples were removed, rinsed with deionized water, and then dried. The thin ZnO layer was eliminated due to sacrificial growth (Figure 1d).


Direct formation of gold nanoparticles on substrates using a novel ZnO sacrificial templated-growth hydrothermal approach and their properties in organic memory device.

Goh LP, Razak KA, Ridhuan NS, Cheong KY, Ooi PC, Aw KC - Nanoscale Res Lett (2012)

Process flow for sacrificial templated-growth hydrothermal reaction of AuNPs embedded in the PMMSQ memory device. (a) PMMSQ/n-Si, (b) deposited ZnO layer, (c) thermal oxidation of ZnO layer to form ZnO seeds, (d) AuNPs formed on PMMSQ/n-Si, (e) another PMMSQ layer was deposited on the AuNPs, and (f) desired memory device structure with Al as top and bottom electrodes.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
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getmorefigures.php?uid=PMC3526390&req=5

Figure 1: Process flow for sacrificial templated-growth hydrothermal reaction of AuNPs embedded in the PMMSQ memory device. (a) PMMSQ/n-Si, (b) deposited ZnO layer, (c) thermal oxidation of ZnO layer to form ZnO seeds, (d) AuNPs formed on PMMSQ/n-Si, (e) another PMMSQ layer was deposited on the AuNPs, and (f) desired memory device structure with Al as top and bottom electrodes.
Mentions: A n-type (100) silicon wafer was cut into small pieces (dimension of 1 × 1 cm) and used as substrates. The silicon substrates were cleaned using a standard RCA cleaning process to remove the organic and inorganic contaminants from the surface. A polymethylsilsequioxane (PMSSQ) layer was deposited at 2,000 rpm for 100 s on the cleaned substrates to achieve 350-nm dielectric layers. Thereafter, the samples were cured in an oven at 160°C for 1 h (Figure 1a). A 200-nm-thick ZnO thin film was then deposited on each substrate using radio-frequency magnetron sputtering at 200 W (Figure 1b).The samples were annealed at different temperatures: 200°C, 300°C, and 400°C, with a ramp rate and soaking time of 5°C/min and 10 min, respectively, to observe the seed layer effects on AuNP formation (Figure 1c). Thereafter, the AuNPs were grown on the ZnO seed template using a sacrificial low-temperature hydrothermal approach. The ZnO-seeded samples were subjected to a hydrothermal reaction in a preheated oven at 80°C for 4 h. The hydrothermal bath contained 0.1 M zinc nitrate tetrahydrate (Zn(NO3)2·4H2O), 0.1 M hexamethylenetetramine (C6H12N4), 0.01 M gold(III) chloride trihydrate (AuCl4.3H2O), and 10 mL acetic acid. After hydrothermal reaction, the samples were removed, rinsed with deionized water, and then dried. The thin ZnO layer was eliminated due to sacrificial growth (Figure 1d).

Bottom Line: Well-distributed and controllable AuNP sizes were successfully grown directly on the substrate, as observed using a field emission scanning electron microscope followed by an elemental analysis study.In this study, the AuNPs were charge-trapped sites and showed excellent memory effects when embedded in PMSSQ.Optimum memory properties of PMMSQ-embedded AuNPs were obtained for AuNPs synthesized on a seeded ZnO template annealed at 300°C, with 54 electrons trapped per AuNP and excellent current-voltage response between an erased and programmed device.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, Nibong Tebal, Penang 14300, Malaysia. khairunisak@eng.usm.my.

ABSTRACT
This study describes a novel fabrication technique to grow gold nanoparticles (AuNPs) directly on seeded ZnO sacrificial template/polymethylsilsesquioxanes (PMSSQ)/Si using low-temperature hydrothermal reaction at 80°C for 4 h. The effect of non-annealing and various annealing temperatures, 200°C, 300°C, and 400°C, of the ZnO-seeded template on AuNP size and distribution was systematically studied. Another PMMSQ layer was spin-coated on AuNPs to study the memory properties of organic insulator-embedded AuNPs. Well-distributed and controllable AuNP sizes were successfully grown directly on the substrate, as observed using a field emission scanning electron microscope followed by an elemental analysis study. A phase analysis study confirmed that the ZnO sacrificial template was eliminated during the hydrothermal reaction. The AuNP formation mechanism using this hydrothermal reaction approach was proposed. In this study, the AuNPs were charge-trapped sites and showed excellent memory effects when embedded in PMSSQ. Optimum memory properties of PMMSQ-embedded AuNPs were obtained for AuNPs synthesized on a seeded ZnO template annealed at 300°C, with 54 electrons trapped per AuNP and excellent current-voltage response between an erased and programmed device.

No MeSH data available.