Ng , Soo Ai (2016) Fabrication of gold nanoparticles using low hydrothermal reaction for memory application. PhD thesis, Universiti Sains Malaysia.
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Abstract
Pembentukan partikel nano emas (AuNPs) yang bertaburan pada peranti memori adalah isu utama apabila menghadapi masalah pengecilan peranti memori. AuNPs telah berjaya dihasilkan dengan menggunakan templat Aluminium (Al) atau Zink (Zn) di atas substrat Silikon (Si) atau gelas ITO dengan menggunakan kaedah hidroterma suhu rendah. Al dan Zn telah dipilih sebagai templat kerana sempadan bijian didapati akan menjadi tempat untuk pembentukan AuNPs. Dalam penyelidikan ini, Al dan Zn telah dideposit di atas substrat Si, manakala hanya Al didepositkan di atas substrat gelas ITO. Kesan suhu penyepuhlindapan ke atas templat, tempoh tindak balas hidroterma (1-5 h), kepekatan HAuCl4 (0.001-0.020 M), kepekatan Al(NO3)3 (0.01-0.20 M), dan kepekatan Zn(NO3)2 (0.01-0.20 M) pada pembentukan AuNPs telah dikaji. Hasil optimum diperolehi daripada substrat Si dengan struktur AuNPs kubik berpusat muka (FCC) dibentukkan pada Al terdiri daripada saiz partikel 80 ± 4 nm dan 42 ± 7 nm dengan 1.29 x 1012 dan 2.71 x 1012 m-2 kawasan kepadatan untuk AuNPs bersaiz besar dan kecil masing-masing. Sampel optima ini mempamerkan sifat memori dengan ambang voltan rendah (Vth) sebanyak 2.2 V dan 284 caj tersimpan untuk setiap AuNP terbentuk. Mekanisma konduksi AuNPs terbentuk dalam lapisan organik pada voltan rendah mematuhi kesan termionik dengan gabungan Schottky dan Poole Frenkel. Untuk voltan medium, mekanisma konduksi melibatkan pengaliran diikuti caj terperangkap terhad semasa (TCLC). Manakala pada voltan tinggi mekanisma konduksi adalah caj jarak terhad semasa (SCLC). Dalam usaha untuk mengkaji peranti memori yang lut sinar, taburan baik AuNPs dengan 135 ± 28 nm dan 89 ± 11 nm untuk saiz partikel besar dan kecil di atas gelas ITO menghasilkan keupayaan penyimpanan caj yang baik. Taburan terpencil AuNPs menyumbang kepada sifat peranti memori yang baik kerana meningkatkan sifat-sifat kawasan permukaan. ________________________________________________________________________________________________________________________ Formation of well distributed Gold nanoparticles (AuNPs) on memory devices is the main issue upon facing scaling down dilemma. AuNPs were successfully grown on the templated silicon (Si) and indium tin oxide (ITO) glass substrates using a low temperature hydrothermal method. In this work, Aluminum (Al) or Zinc (Zn) templates were deposited on the Si substrates, while Al template was deposited on the ITO glass substrate. Al and Zn template have been selected as the template due to defined grain boundaries can be obtained for sites on formation of AuNPs. The effect of annealing temperature of templates, hydrothermal reaction duration (1-5 h), HAuCl4 concentration (0.001-0.020 M), Al(NO3)3 concentration (0.01-0.20 M), Zn(NO3)2 concentration (0.01-0.20 M) on the formation of AuNPs were investigated. The optimum result obtained on Si substrate was the face centered cubic (FCC) AuNPs formed on the non annealed sputtered Al template which consisted of 80 ± 4 nm and 42 ± 7 nm particle size with 1.29 x 1012 and 2.71 x 1012m−2 area density for large and small AuNPs, respectively. The sample exhibited the lowest threshold voltage (Vth) of 2.2 V in I-V analysis and 284 charges stored per AuNP in C-V analysis. The conduction mechanisms of AuNPs embedded in organic layers involved Thermionic emission (TE), Schottky and Poole Frenkel emission in low voltage region. In medium voltage region, trapped charge limited current (TCLC) happened while spaced charge limited current (SCLC) occurred in high voltage region. In terms of transparent memory devices, good distribution of FCC structure AuNPs with 135 ± 28 nm (1.30 x 1012 m-2) and 89 ± 11 nm (3.47 x 1012 m-2) for large and small particle sizes and area density produced charge storage capability of 0.8 V turn “ON” voltage and 74 charges stored per AuNP for the memory device on ITO glass substrate. These findings proved that discrete distribution in combination with large and small AuNPs contributed to excellent memory effects due to enlargement of surface area properties.
| Item Type: | Thesis (PhD) |
|---|---|
| Additional Information: | Full text is available at http://irplus.eng.usm.my:8080/ir_plus/institutionalPublicationPublicView.action?institutionalItemId=2812 |
| Subjects: | T Technology T Technology > TA Engineering (General). Civil engineering (General) > TA1-2040 Engineering (General). Civil engineering (General) |
| Divisions: | Kampus Kejuruteraan (Engineering Campus) > Pusat Pengajian Kejuruteraan Awam (School of Civil Engineering) > Thesis |
| Depositing User: | Mr Mohd Jasnizam Mohd Salleh |
| Date Deposited: | 12 Jul 2018 07:24 |
| Last Modified: | 15 Aug 2018 04:55 |
| URI: | http://eprints.usm.my/id/eprint/41013 |
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