High-Sensitivity MoO3-x/Bi2O2Se Hybrid Photodetector Operating at Wavelengths of O-Band and C-Band

The original band (O-Band) and conventional band (C-Band) are crucial for modern optical communication due to the low energy dissipation in optical fibers. In communication systems, signal conversion at these bands requires sensitive near-infrared (NIR) detectors with response speeds faster than microseconds. However, current commercial junction-based devices for photoreceivers suffer from low responsivity (<1 A/W). Photoconductive devices generally suffer an inferior speed slower than milliseconds. Here, we demonstrate a high-performance substoichiometric molybdenum oxide (MoO
$_{\text {3-{x}}}{)}$
/Bi2O2Se NIR photodetector toward telecommunication wavelengths. Efficient interfacial transfer of hot electrons from plasmonic MoO
$_{\text {3-{x}}}$
and a long carrier lifetime in the Bi2O2Se channel synergistically contribute to the superior performance of the hybrid device. The responsivity of the device reaches ~24 A/W at 1310 nm and 1 A/W at 1550 nm. The rise time reaches 453 ns (bandwidth ~1.2 MHz) at 800 nm, nearly 4 orders of magnitude greater than that of common photoconductive devices. Furthermore, the device shows dramatic capability of weak light detection (~10 nW).