| Investigation on influence of etching time and solution temperature on physical properties of silicon nanowires through 1-MACE method |
| Paper ID : 1353-UFGNSM-FULL |
| Authors: |
|
Somaye Ashrafabadi *1, hosein Eshghi2 1سمنان-شهرستان شاهرود-میدان 7 تیر-دانشگاه صنعتی شاهرود 2shahrood university of technology |
| Abstract: |
| In this paper vertical and ordered silicon nanowire (SiNWs) arrays, were fabricated through one-step metal assisted chemical etching (1-MACE) of lightly doped (100) n-type silicon wafer. The procedure was done in an aqueous etching solution of 4.6M HF/0.1M H2O2/ 0.02M AgNO3 in different etching times of 30 and 60 minutes (min.) at room temperature (RT) etching solution (called S1 and S2, respectively), also one for 60 min. at 50°C (called S3). The surface morphology and structure of samples was investigated by FESEM images. It seems that a critical etching duration is necessary to have SiNWs arrays. Although in S1 we have just (100) porous structure, in S2 and S3 SiNWs arrays with (100) orientation are formed. Then the effect of etching solution temperature was investigated. We found, with increasing the solution temperature the diameters of SiNWs are strongly reduced and have a bundle-like structure shape. These shapes are attributed to the degenerate rigidity and Van der Waals force between the nanowires. Moreover, the optical properties of samples were studied through reflectance spectra in the wavelength range of 400-1100 nm. Results indicate that the average reflectance of the samples is reduced from 50% in bulk silicon to less than 0.5% for SiNWs. For further study the SiNWs band gap was determined using Kubelka– Munk equatioe. We found that the optical band gap of samples is increased to 1.49, 1.57 and 1.75 eV, respectively. Finally, Raman spectra showed a red-shift from ~ 520 cm-1 in bulk-Si to 518 cm-1 in S3. This variation is attributed to the decrease of nano-crystallite size of NWs, which is consistent with the increment of band gaps, due to quantum confinement effect, in these samples. |
| Keywords: |
| silicon nanowire, SiNWs, solution temperature |
| Status : Paper Accepted (Poster Presentation) |
