High-Temperature Mid-Wavelength Infrared Detectors Based on InGaAs/InAsSb Type-II Superlattices With InGaAsSb Barriers

Mid-wavelength infrared detectors based on InGaAs/InAsSb superlattices were successfully grown on InAs substrates by metal-organic chemical vapor deposition (MOCVD). AlSb-free InGaAsSb quaternary alloy was employed as the electron barrier layer to reduce the dark current. By comparing the electrical and optical performances of three PNn devices with different Ga compositions in In<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\mathrm {1-x}}$ </tex-math></inline-formula>GaxAs<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\mathrm {1-y}}$ </tex-math></inline-formula>Sby barriers, the optimal Ga composition was found to be 0.3. At 150 K, the dark current density of this device was <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.2 \times 10^{-4}$ </tex-math></inline-formula> A/cm2 at -0.1 V. The device operates at zero bias with a 50% cutoff wavelength of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim 5.1~\mu $ </tex-math></inline-formula>m, a peak blackbody responsivity of 1.6 A/W, and a peak specific detectivity of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2.5\times 10^{11}~\mathrm {cm\cdot }\sqrt {\mathrm {Hz}} \mathrm {/W}$ </tex-math></inline-formula>.