  A new fabrication process is developed for growing Bi2Se3 topological
insulators in the form of nanowires/nanobelts and ultra-thin films. It consists
of two consecutive procedures: first Bi2Se3 nanowires/nanobelts are deposited
by standard catalyst free vapour-solid deposition on different substrates
positioned inside a quartz tube. Then, the Bi2Se3, stuck on the inner surface
of the quartz tube, is re-evaporated and deposited in the form of ultra-thin
films on new substrates at temperature below 100 {\deg}C, which is of relevance
for flexible electronic applications. The method is new, quick, very
inexpensive, easy to control and allows obtaining films with different
thickness down to one quintuple layer (QL) during the same procedure. The
composition and the crystal structure of both the nanowires/nanobelts and the
thin films is analysed by different optical, electronic and structural
techniques. For the films, scanning tunnelling spectroscopy shows that the
Fermi level is positioned in the middle of the energy bandgap as a consequence
of the achieved correct stoichiometry. Ultra-thin films, with thickness in the
range 1-10 QLs deposited on n-doped Si substrates, show good rectified
properties suitable for their use as photodetectors in the ultra
violet-visible-near infrared wavelength range
