The Nano4NPS group started its activities at the beginning of the eighties.

Current research focuses on:

Nanostructures: formation and characterization

The materials currently investigated include Si nanowires and nanocrystals, porous Si, porous anodic alumina and others. The techniques used include electrochemistry, metal-assisted chemical etching, low pressure chemical vapour deposition (LPCVD), sputtering and electron gun evaporation.

Nanostructures: Applications in Electronics and sensors

The Electronic devices currently investigated include on-chip RF passive devices integrated on a nanostructured porous Si substrate (CPWs, inductors, antennas), and memory devices.

Main research achievements

Worldwide pioneering research results of the group include the following:

• Developed, for the first time worldwide, Si nanowires using lithography and etching and observed visible light emission from them (Appl. Phys. Letters, 66(9), 1114, (1995), Physica Status Solidi, (b) 190, 91, (1995), J. Vacuum Science and Technol. B 15(3) 640, (1997))
• Developed, for the first time worldwide, an electroluminescent device based on silicon nanowires (nanopillars) (Appl. Phys. Letters, 69(15), 2267, (1996), Thin Solid Films, 297, 176,  (1997)). Phys. St. Sol. (a) 165,79, (1998)
• Investigated different effects in Si nanocrystals embedded in SiO₂ or CaF₂ and in Si nanowires, as follows:

Polarized Raman and Photoluminescence in silicon nanowires, J. Appl. Phys. 84(2), 1059-1063, (1998), Stable-photo and electroluminescence from Si nanocrystals embedded in SiO₂ (Appl. Phys. Lett, 77 (12),  1816, (2000), Phys. St. Sol. (a) 165,79, (1998)), Dependence of the radiative recombination lifetime on electric field in silicon nanocrystals embedded in SiO₂, Europhys. Lett, 51 (2), 168, (2000), Self-trapped excitons in silicon nanocrystals of sizes below 1.5 nm in Si/ SiO2 multilayers, Jour. of Appl. Phys., 90(11), 5735, (2001), Electroluminescence from silicon nanocrystals in Si/CaF2 superlattices (Appl. Phys. Lett., 79(13) 2076, (2001)), Light emission and non-linear transport in Si nanocrystals/CaF₂ superlattices, J. of Luminescence, 22, 2313, (1998) Mat. Sci. & Engin. B69-70, 546-548, (2000), Photoluminescence lifetimes in silicon nanowires, (Phys. Rev. B, vol. 66, 205 323, (2002)), Si nanocrystals under high hydrostatic pressure: Increased phase transition Physical Rev. B, 58(21), 14089, (1998), Polarized Raman and Photoluminescence studies in silicon nanowires, J. Appl. Phys. 84(2), 1059-1063, (1998), Charging/discharging properties of Si and Ge nanocrystals with application in nanocrystal memories (Appl. Phys. Lett. 82(3) 397, (2003), Nanotechnology 15, 1-7, 1233-1239, (2004), Nanotechnology 15, 1-5, 352-356, (2004), J. Nanosci. Nanotechnol., vol. 7, 316-321 (2007), J. Nanosci. Nanotechnol., vol. 7, 368-373 (2007)

• Based on the low thermal conductivity of porous Si, proposed a novel thermal isolation platform on the Si wafer. Developed different thermoelectric and sensor devices using thick porous Si layers for thermal isolation (Sens. & Actuators A, 76(1-3) p.133, (1999), Phys. Stat. Sol. (a) 182,307, (2000), IEEE Sensors Journal, Vol. 2 (2) 1530, (2002), Sensors & Actuators A, 100, 413-422, (2004), IEEE Sensors Journal, 2(5), 463-475, (2002), Sensors and Actuators B: Chemical, 95(1-3), 78, (2003)).  Currently investigates porous Si for use in cooling devices on the Si wafer.
• Developed bulk Si micromachining for suspended membranes and cantilevers on Si using porous Si as sacrificial layer. Developed porous Si membranes for sensors and microfluidics (Microelectronic Engineering, 35, 397, (1997), Sensors and Actuators A68, 429-434 (1998), IEEE J. Microelectromech. Syst , 12 (6),  863, (2003), J. of Micromech. & Microengin. 13, 323, (2003), Phys. Stat. Sol. (a), 197 (2), 539, (2003)
• Developed highly ordered porous anodic alumina thin films on Si for use as templates for nanostructure growth on Si, as masking layers in Si nanopatterning and as active layers in nanodevices (Nanotechnology 16, 103, (2005), Ionics, 11 (3-4), 236 (2005), Nanotechnology 19, 495306 (2008), Physica Status Solidi (A) Applications and Materials, 206 (6), pp. 1286-1289, 2009, Physica Status Solidi (A) Applications and Materials, 206 (6), pp. 1309-1312, 2009 Journal of Applied Physics 107 (11), art. no. 113104 (2010) IEEE Transactions on Electron Devices 57 (10), art. no. 5535075, pp. 2679-2683 2010
• Developed and investigated the use of porous Si thick layers for RF shielding on the Si wafer