Uncooled infrared detectors have aroused keen interest in narrow bandgap semiconductor research. We propose to use Bismuth Telluride (Bi 2Te3) bandgap energy of about 0.15 eV for middle wavelength IR (MWIR) detection. In this work, a heterojunction structure of Bi2Te3/GaN/Al2O3 was fabricated to form a photovoltaic detector. The structural properties of Bi2Te 3 thin films were characterized by high resolution x-ray diffraction spectroscopy. Crystallinity of Bi2Te3 thin films was found to be strongly dependent on deposition temperatures. The spectral current responsivity for this heterojunction in NIR-to-MWIR region was evaluated under back-side illumination. The devices were also characterized by studying their low-frequency noise spectra measurement. The experimental results suggest that, the noise level of the devices is correlated to the crystallinity of the Bi 2Te3 thin films.
ASJC Scopus subject areas
- Physics and Astronomy(all)