Strong quantum confinement effect in the optical properties of ultrathin   {\alpha}-In2Se3
  The effect of quantum confinement in the optical absorption spectra of atomically thin {\alpha}-In2Se3 crystals is studied, observing a huge thickness-dependent shift in the optical band gap of exfoliated {\alpha}-In2Se3 flakes. The band gap variation reported here is among the largest found in semiconductor crystals and spans a region of the near-UV spectrum uncovered by other 2D semiconductors. 
Jorge Quereda, Robert Biele, Gabino Rubio-Bollinger, Nicol\'as   Agra\"it, Roberto D'Agosta, Andres Castellanos-Gomez
cond-mat.mes-hall cond-mat.mtrl-sci