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Aligned, open-tipped carbon nanotube arrays of high density and uniformity were synthesized via a flame method on silicon substrates using a nanoporous template of anodized aluminum oxide from which the nanotubes were grown. The diameter and length of the nanotubes are controlled by the geometry of the aluminum oxide template. These results show the feasibility of integration between carbon nanotube arrays and silicon microelectronics.

Photovoltaic effect measurements have been carried out for the strained Si1−xGex/Si multiple quantum well samples. The absorption structures of the transitions from heavy‐hole ground state (HH0) to the unconfined conduction (EC) states, light‐hole ground state to EC states as well as the transitions of phonon (transverse acoustic and transverse optical)‐assisted HH0‐EC excitons of the sample with x=0.25 are identified by the photovoltaic measurement at the temperature of 18 K. The agreement between the experimental results and the calculations based on simple theoretical models is fairly good. Due to the rapid increase of the background absorption, the structures of the transitions from excited hole subbands to the conduction states are very difficult to identify. For the sample with x=0.5, the absorption related to the defects originated from the partial relaxation of the large misfit strain between Si0.5Ge0.5 and Si gives a great influence upon the identification of the interband absorption structures o...