Epitaxial Growth of Bi2Se3 Infrared Transparent Conductive Film and Heterojunction Diode by Molecular Beam Epitaxy

Epitaxial n -type infrared transparent conductive Bi 2 Se 3 thin film was cultivated by molecular beam epitaxy (MBE) method on Al 2 O 3 (001) substrate. The orientation between Bi 2 Se 3 and the substrate is Bi 2 Se 3 (001)//Al 2 O 3 (1 2¯ 10). Conducting mechanism ensued the small-polaron hopping mechanism, with an activation energy of 34 meV. The film demonstrates conductivity of n -type, and the resistivity is 7 × 10 −4 Ωcm at room temperature. The Film exhibits an excellent carrier mobility of 1,015 cm 2 /Vs at room temperature and retains optical transparency in the near-infrared (>70%) and far-infrared (>85%) ranges. To the best of our knowledge, the Bi 2 Se 3 film yields the best result in the realm of n -type Infrared transparent conductive thin films generated through either physical or chemical methods. To demonstrate the application of such films, we produced N-Bi 2 Se 3 /P-CuScO 2 heterojunction diode device, the ∼3.3 V threshold voltage of which conformed fairly well with the CuScO 2 bandgap value. The high optical transparency and conductivity of Bi 2 Se 3 film make it very promising for optoelectronic applications, where a wide wavelength range from near-infrared to far-infrared is required.