Wide band photodetectors based on Bi2Se3 Topological Insulator

$\mathrm{Bi}_{2} \mathrm{Se}_{3} / \mathrm{n}-\mathrm{Si}$ heterojunctions have been successfully obtained by depositing BirSes films with thickness in the range $10 \mathrm{~nm}-100 \mathrm{~nm}$ on pre-patterned ndoped Si substrates by vapor solid deposition method. The samples present on/off ratio of the order of $10^{5}$ and dark current in the range of 10nA. When illuminated with He-Ne radiation through the Bi
2
Se
3
layer, the unbiased detectors show very high linearity, responsivity as high as $60 \mathrm{~mA} / \mathrm{W}$ and Detectivity in the range of $10^{11}$ Jones.