Large Format AlInAs–InGaAs Quantum-Well Infrared Photodetector Focal Plane Array For Midwavelength Infrared Thermal Imaging

We report the first large format (640times512) AlInAs-InGaAs quantum-well infrared photodetector (QWIP) focal plane array (FPA), and investigate the characteristics of AlInAs-InGaAs QWIPs both at pixel and FPA level. The measurements on the detectors fabricated with molecular beam epitaxy grown epilayer structure including 30 InGaAs quantum wells (26 Aring thick, N_D=2times10¹⁸ cm^-3) yielded very promising characteristics. The detectors with lambda_p=4.2 mum and Deltalambda/lambda_p=25% displayed a background-limited performance temperature as high as 105 K with f/2 aperture. The noise equivalent temperature difference of the FPA is as low as 23 mK (f/1.5) at 105-K sensor temperature with 99.6% operability. These results are comparable to the best results reported for AlGaAs-InGaAs midwavelength infrared QWIPs showing the promise of this material system for completely lattice-matched multiband QWIP FPAs.