InP-Based Near Infrared/Extended-Short Wave Infrared Dual-Band Photodetector

In this paper, InP based near infrared (NIR) /extended-short wave infrared (eSWIR) dual-band photodetector with In 0.53 Ga 0.47 As and In 0.53 Ga 0.47 As/GaAs 0.5 Sb 0.5 type-II superlattice (T2SL) back-to-back n-i-p/p-i-n structures is demonstrated. Monolithic growth of NIR/eSWIR dual-band photodetector on InP substrate enjoys the benefit of the lattice matched property of InP/InGaAs/GaAsSb material system. Low optical crosstalk (below −10 dB) between the two sub-detector is achieved for wavelength range out of 1690–1750 nm. At room temperature, the device exhibits a dark current density of <tex-math notation="LaTeX">1.26× 10 ⁻⁵ </tex-math> A/cm 2 for In 0.53 Ga 0.47 As sub-detector under −0.1 V bias and <tex-math notation="LaTeX">3.78× 10 ⁻² </tex-math> A/cm 2 for In 0.53 Ga 0.47 As/GaAs 0.5 Sb 0.5 sub-detector under −1 V bias. The corresponding responsivity and specific detectivity are 0.57 A/W and <tex-math notation="LaTeX">2.63× 10 ¹¹ </tex-math> cm <tex-math notation="LaTeX">· </tex-math> Hz <tex-math notation="LaTeX">1/2 </tex-math> /W at 1640 nm for NIR sub-detector and 0.22 A/W and <tex-math notation="LaTeX">1.96× 10 ⁹ </tex-math> cm <tex-math notation="LaTeX">· </tex-math> Hz 1/2 /W at <tex-math notation="LaTeX">2~μ m </tex-math> for eSWIR sub-detector, respectively. The characterization results show the potential for monolithically growing dual-band SWIR photodetector on InP substrate with low dark current density for SWIR applications.