Abstract Submitted to the    NANOTUBE'04 Conference:

Carbon nanotubes with their unique combination of electronic, thermal and mechanical properties hold promise for nano-electronic as well nano-optical devices. Beneficial for application in such devices is the tuneability of optical band gaps by tube structure throughout almost the entire near infrared range. A careful look at optical absorption and photoluminescence spectra reveals the nature of optical excitations in CNTs and the role of the detailed tube structure for transition energies and band gaps. In double-wall CNTs, the addition of a 'second skin' makes studies of the dynamics of optical excitations of the inner core-tubes particularly fascinating. We present time-resolved photoluminescence studies of SWNTs and DWNTs and discuss the observed carrier dynamics and relaxation processes in different environments.