Post Annealing Effects on <inline-formula> <tex-math notation="LaTeX">$\text{Er}_{2}\text{O}_{3}$ </tex-math> </inline-formula> Nanowire Arrays for Improved Photodetection

Abstract

The Er <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> nanowires (NWs) arrays were synthesized on Si substrate by Glancing angle deposition technique. The field emission gun scanning electron microscopy showed the vertically aligned highly porous NWs. The transmission electron microscopy showed the unsymmetrical growth of NWs. Polycrystalline nature of NWs along with the orientation of crystal planes were obtained from selected area electron diffraction analysis. X-ray diffraction showed the improvement of the crystal quality with increase in annealing temperature (up to 550 °C), but further rise in annealing temperature (750 °C) showed a reduction in the film crystal quality. Averagely, 1.4 times enhanced absorption was observed in 550 °C annealed sample compared to the as-deposited sample. Ag metal contact was deposited to fabricate Ag/Er <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> /Si MIS structure. The device fabricated with 550 °C annealed Er <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> NW showed better characteristics as compared to other samples in terms of low dark current density (4.5 × 10-9 A/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ), high sensitivity ( 9 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> ), and fast response (t <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</sub> = 0.28 and t <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</sub> = 0.18 sec). Moreover, a high responsivity of 0.527 A/W, high detectivity of 1.18 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</sup> jones with NEP as low as 2.37 pW, was obtained for 550 °C.