42 research outputs found
Study of the temperature distribution in Si nanowires under microscopic laser beam excitation
Get PDFThe use of laser beams as excitation sources for the characterization of semiconductor nanowires (NWs) is largely extended. Raman spectroscopy and photoluminescence (PL) are currently applied to the study of NWs. However, NWs are systems with poor thermal conductivity and poor heat dissipation, which result in unintentional heating under the excitation with a focused laser beam with microscopic size, as those usually used in microRaman and microPL experiments. On the other hand, the NWs have subwavelength diameter, which changes the optical absorption with respect to the absorption in bulk materials. Furthermore, the NW diameter is smaller than the laser beam spot, which means that the optical power absorbed by the NW depends on its position inside the laser beam spot. A detailed analysis of the interaction between a microscopic focused laser beam and semiconductor NWs is necessary for the understanding of the experiments involving laser beam excitation of NWs. We present in this work a numerical analysis of the thermal transport in Si NWs, where the heat source is the laser energy locally absorbed by the NW. This analysis takes account of the optical absorption, the thermal conductivity, the dimensions, diameter and length of the NWs, and the immersion medium. Both free standing and heat-sunk NWs are considered. Also, the temperature distribution in ensembles of NWs is discussed. This analysis intends to constitute a tool for the understanding of the thermal phenomena induced by laser beams in semiconductor NWs
The white throated form of the pied wheatear Oenanthe pleschanka in Kenya
No full textVolume: 3Start Page: 79End Page: 8
Ethiopian region birds attracted to the lights of Ngulia safari lodge, Kenya
No full textVolume: 1Start Page: 98End Page: 10
Ringing and migration at Ngulia, Tsavo, autumn 1991
No full textVolume: 15Start Page: 172End Page: 17
Melodious warbler Hippolais polyglotta at Ngulia, Kenya - first record for East Africa
No full textVolume: 20Start Page: 43End Page: 4
