InP-Based Broadband Photodetectors With InGaAs/GaAsSb Type-II Superlattice

In this work, an In
_0.53
Ga
_0.47
As/GaAs
_0.5
Sb
_0.5
type-II superlattice(T2SL) based broadband photodetector with an optical spectrum response ranging from 250 nm to 2400 nm is demonstrated. The photodetector shows a low dark current density of
$3.48\times 10^{-4}$
A/cm
²
under the bias of −1 V and a specific detectivity (D*) of
$1.59\times 10^{10}$
cm
$\cdot $
Hz1/2/W at
$2 ~\mu \text{m}$
at 293 K. A recessed window on the surface of the top P layer was fabricated to enhance the responsivity of ultraviolet (UV) and visible band. The UV and visible band quantum efficiency (QE) can increase by 40% with the recessed window.