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In this paper, silicon nanowires formation on N-type crystalline silicon wafer is studied. Metal-assisted chemical etching (MACE) technique is used in this study because it’s low cost but can produce a high-aspect-ratio of silicon nanowires. High-aspect-ratio silicon nanostructures have been proved as an effective texture for light trapping on silicon solar cells surfaces. The photons from incident light can be trap on the silicon nanowires and then being absorb into the cells which resulting high efficiency silicon solar cells. Traditionally, MACE works by creating a holes using metal catalyst such as Ag or Au in order to reduce of the etchant. The hydrofluoric acid (HF) and hydrogen peroxide (H 2 O 2 ) are function to etched the metal native oxide thus create a pores or nanowires formation. Roughness parameters of silicon nanowires was investigate in order to see the texture of silicon nanowires is rough enough to trap more photons on silicon wafer surfaces. Hence, roughness parameters are very important for texturing silicon wafer surfaces. In this study, root mean square (RMS) is used as an indicators for which acquired from the line profiles. Results from the roughness parameters shown a good compatibility.

Silicon nanostructures are one of the candidates for tomorrow technologies due to its novel physical properties. High-aspect-ratio silicon nanostructures have been proved as effective microstructures for enhance silicon solar cells efficiency. Silicon nanowires enhance solar cells efficiency by formation vertical well aligned nanowires on the top surfaces which give effects to the optical, electronic and physical properties of silicon solar cells. Silicon nanowires also can enhance the carrier collection of photovoltaic devices. There are two types of methods used to fabricate silicon nanowires such as top-down or bottom-up fabrication. One of the techniques to get high-aspect-ratio nanostructures is by using metal-assisted chemical etching (MACE). Metal-assisted chemical etching (MACE) technique has been adopted in many research experiments and technology due to its low cost fabrication of silicon nanowires but can form a high-aspect-ratio of silicon nanowires. MACE has demonstrates outstanding results of silicon nanowires in improving many microelectronics and photonic devices. Traditionally, MACE is operated by making a holes using metal catalyst in order to reduce of using the etchant. The mobility of the reactants impeded when the height of silicon nanowires increases which resulting insufficient holes. However, MACE also has advantages and drawbacks which appear such as long-vertical-well aligned silicon nanowires and some broken silicon nanowires due to very thin silicon nanowires which easily to break, respectively. In this paper, different solutions concentration is study using a two-step MACE process. The chemical solution contains HF/AgNO 3 and also H 2 O 2 . The experiment is conducted at room temperature. During the etching process, anisotropic growth different silver particles which used for the formation of the silicon nanowires on silicon wafer surfaces. As a results, the etch rate gives the effect on the silicon nanowires length. A comparative study of etch rate has been conducted in order to see clearly the differences.