Infrared Barrier Detectors With Metamorphic InAsSb Absorbers on GaAs Substrates

We investigate barrier detectors based on metamorphic InAsSb operating above 200 K. Different detectors’ structures covering the infrared (IR) range from 3 to
$17~\mu \text{m}$
were MBE grown on GaAs substrates. Selected issues concerning the barrier detectors’ structure design, growth, processing, and measurements were indicated. InAs
$_{{1}-{x}}$
Sbx exhibits a relatively strong dependence of Sb composition x on the lattice constant, and therefore, the buffer layers were chosen individually for each waveband. Theoretical simulations by the APSYS numerical platform (Crosslight) support detectors’ design and help to overcome the unwanted energetic barriers due to the valence band offset (VBO). Secondary ion mass spectroscopy (SIMS) profile analysis lets to compare actual MBE-grown InAsSb detector architecture with the intentional design. Current–voltage and spectral characteristics measurements determined the quality of obtained detectors and allowed them to calculate their detectivity. The performance of developed InAsSb detectors was compared with the state-of-the-art mercury cadmium telluride (MCT) devices. Recent advances in InAsSb barrier detectors allowed their room temperature detectivities to achieve
$5\times 10^{{9}}$
,
$2\times 10^{{9}}$
, and
$2\times 10^{{7}}$
cm
$\cdot $
Hz
$^{{1}/{2}}\cdot \text{W}^{-{1}}$
at SWIR, MWIR, and LWIR spectral ranges, respectively, confirming the importance of III–V materials in the IR industry.