Black-Arsenic/Germanium-on-Insulator Heterostructure Field Effect Transistor for Ultrafast Polarization Sensitive Short-Wave Infrared Photodetection

Purely monolithic or hybrid-monolithic integration of CMOS compatible platforms with IR active optical components can be a rewarding advancement towards scalable group IV MIR photonics. Here, a polarization-sensitive SWIR phototransistor based on black arsenic (b-As) and germanium (Ge) heterojunction is discussed. The device responds to a broad range of light spectrum (0.6 – 4
$\mu \text{m}$
). In the SWIR infrared band, the device has a high responsivity (402 A/W at 3
$\mu \text{m}$
), high detectivity (3.78
$\times 10^{{11}}$
Jones), low noise equivalent power (4.4
$\times10$
-15 WHz
^1/2
), and a fast response (14.6
$\mu $
sec). Due to the anisotropy observed in b-As, the device also demonstrated highly polarization sensitive photocurrent. The present study opens up new avenues for 2D materials-based polarization sensitive CMOS compatible optical platforms.