A Systematic Study of Metal-assisted Chemical Etching Parameters for Well-Ordered Silicon Nanowire Array Fabrication
- PDF / 233,736 Bytes
- 5 Pages / 432 x 648 pts Page_size
- 35 Downloads / 206 Views
A Systematic Study of Metal-assisted Chemical Etching Parameters for Well-Ordered Silicon Nanowire Array Fabrication Arif S. Alagoz, and Tansel Karabacak Department of Applied Science, University of Arkansas at Little Rock, Little Rock, AR 72204, USA ABSTRACT Metal-assisted chemical etching is a simple and low-cost silicon nanowire fabrication method which allows control of nanowire diameter, length, shape and orientation. In this work, we fabricated well-ordered silicon nanowire array by patterning gold thin film by nanosphere lithography and etching single crystalline silicon wafer by metal-assisted chemical etching technique. We investigated relation between etched solution concentration and nanowire morphology, wafer crystal orientation, etching rate. This well-ordered silicon nanowires arrays have the potential applications in many fields but especially next generation energy related applications from solar cells to lithium-ion batteries. INTRODUCTION Metal-assisted chemical etching is a simple, low-cost and scalable technique enabling fabrication of semiconductor nanowires at desired cross-section shape, length, while preserving crystal orientation, doping type and level of starting substrate1. This simple nanowire fabrication method took attention of many researchers and applications in solar cells2, 3, 4, thermoelectrics5, Li-ion batteries6, 7 and hydrophobic surfaces8 are demonstrated. Until now, various fabrication approaches were developed but the most popular of these approaches is single step nanowire fabrication by immersing silicon into metal salt and hydrofluoric acid (e.g. AgNO3:HF) solution2, 9, 10 . In this approach, metal nanoparticle formation on the silicon surface is followed by silicon wafer etching and silicon nanowire formation. Despite its simplicity, random distribution of metal particle size and their position on silicon surface results in random distribution silicon nanowire size and position. Another approach is two step fabrication which starts with depositing and patterning a metal thin film on the sample, following immersion of sample into oxidizing and hydrofluoric acid (e.g. H2O2:HF) solution. By this way, well-ordered silicon nanowires at desired cross-section shape and separation can be fabricated11. In this work, we fabricated well-ordered silicon nanowire array by patterning gold thin film by nanosphere lithography technique and etching single crystalline silicon wafer by metalassisted chemical etching. We investigated relation between etching rate and nanowire morphology with starting wafer crystal orientation, etching solution concentration and etching time. EXPERIMENT (100) and (111) oriented single crystal p-type silicon wafers at resistivity 1-10 ȍǜcm with native oxide were cleaned by following RCA-I procedure. Samples were dipped into
101
NH4OH(30%) : H2O2(30%) : H2O = 1 : 1 : 5 solution at 80oC for 15 minutes, rinsed with deionized water and dried with nitrogen gas. This cleaning process not only removed organic contamination on the samples’ surface but also increase
Data Loading...
