Energy band diagram for the photo-electrochemical etching reaction of n-type (100) silicon
| Autor: | Wern-Dare Jheng, 鄭文達 |
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| Rok vydání: | 2005 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 93 The aim of this work was to build a thermodynamic energy band diagram for the system of n-type Si (100)/HF that is in dynamic equilibrium at the interface. The concept of the diagram was based on the shift of energy levels such as Fermi energy (EF), conduction band energy (Ec), and valence band energy (Ev) before and after the contact of silicon with HF solutions. Through measurements of the open circuit potential (OCP) and flatband voltage (Vfb), the energy band diagram for the Si/HF system was established. This diagram was useful in estimation of the activation energy for the photo-electrochemical etching system. The kinetic study demonstrated that the etching rate of the silicon (1) increases with an increase of illumination power; (2) increases to a maximum with HF from 0.5 to 2.0 M then decreases with further increase of the HF concentration; (3) accelerates in the presence of 5-10 M EtOH to form smooth macropores but decelerates and caues severe side-etching on the pore walls with the concentration of EtOH reaching 15 M. Based on the energy band diagram established and the electrochemical kinetic data measured, the author was in an attempt to make clear the mechanism for the photo-electrochemical reaction of the n-Si/HF system. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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