To access the full text documents, please follow this link:

Ultraviolet laser patterning of porous silicon
Vega Lerín, Fidel; Pelaez de Fuentes, Ramon Javier; Khun, Timo; Afonso Rodriguez, Carmen Nieves; Recio Sanchez, Gonzalo; Martin Palma, Raul Jose
Universitat Politècnica de Catalunya. Departament d'Òptica i Optometria; Universitat Politècnica de Catalunya. GOAPI - Grup d'Òptica Aplicada i Processament d'Imatge
This work reports on the fabrication of 1D fringed patterns on nanostructured porous silicon (nanoPS) layers (563, 372, and 290nm thick). The patterns are fabricated by phase-mask laser interference using single pulses of an UV excimer laser (193nm, 20ns pulse duration). The method is a single-step and flexible approach to produce a large variety of patterns formed by alternate regions of almost untransformed nanoPS and regions where its surface has melted and transformed into Si nanoparticles (NPs). The role of laser fluence (5-80mJcm-2), and pattern period (6.3-16µm) on pattern features and surface structuring are discussed. The results show that the diameter of Si NPs increases with fluence up to a saturation value of 75nm for a fluence ˜40mJcm-2. In addition, the percentage of transformed to non-transformed region normalized to the pattern period follows similar fluence dependence regardless the period and thus becomes an excellent control parameter. This dependence is fitted within a thermal model that allows for predicting the in-depth profile of the pattern. The model assumes that transformation occurs whenever the laser-induced temperature increase reaches the melting temperature of nanoPS that has been found to be 0.7 of that of crystalline silicon for a porosity of around 79%. The role of thermal gradients across the pattern is discussed in the light of the experimental results and the calculated temperature profiles, and shows that the contribution of lateral thermal flow to melting is not significant for pattern periods =6.3µm.
Àrees temàtiques de la UPC::Enginyeria electrònica::Optoelectrònica::Làser
Àrees temàtiques de la UPC::Enginyeria dels materials
Àrees temàtiques de la UPC::Física
Ultraviolet radiation
Porous silicon
Sponsor: DAAD
German Academic Exchange Service
Raigs ultraviolats
Materials nanoestructurals
Attribution-NonCommercial-NoDerivs 3.0 Spain
American Institute of Physics (AIP)

Show full item record

Related documents

Other documents of the same author

Pelaez de Fuentes, Ramon Javier; Afonso Rodriguez, Carmen Nieves; Vega Lerín, Fidel; Recio Sanchez, Gonzalo; Torres Costa, Vicente; Manso Silvan, Miguel; Garcia Ruiz, Josefa Predenstinacion; Martin Palma, Raul Jose
Pelaez de Fuentes, Ramon Javier; Khun, Timo; Vega Lerín, Fidel; Afonso Rodriguez, Carmen Nieves
Recio Sánchez, Gonzalo; Pelaez de Fuentes, Ramon Javier; Vega Lerín, Fidel; Martín Palma, Raúl José
Vega Lerín, Fidel; Alba Bueno, Francisco; Millán Garcia-Varela, M. Sagrario
Gil Arnal, Miguel Ángel; Varón Puentes, Maria Consuelo; Cardona Torradeflot, Genís; Vega Lerín, Fidel; Buil, José A.