The growth and characterization of two new P-type compressively strained layer InGaAs/AlGaAs/GaAs quantum well infrared photodetectors for mid- and long-wavelength infrared detection

Abstract

Investigation of two p-type compressively-strained layer (PCSL) InGaAs/AlGaAs/GaAs quantum well infrared photodetectors (QWIPs) grown on (10 0) semi-insulating (SI) GaAs substrate has been carried out. The first detector uses a step-bound-to-miniband (SBTM) transition scheme for long wavelength infrared (LWIR) detection and has a detection peak at 10.4 μm with a full width at half-maximum bandwidth, Δλ/λ p = 20%. A responsivity of 28 mA/W was obtained for this detector at T = 65 K and V = 3.0 V, with a spectral detectivity D* = 1.4 x 10 9 cm Hz 1/2 W -1 at T = 65 K and V = 1.0 V. The detector was under the background limited performance (BLIP) at T = 40K and V ≤ 2.0 V. The second detector is a two-color stacked QWIP composed of a PCSL In 0.2 Ga 0.8 As/Al 0.3 Ga 0.7 As QWIP for the MWIR detection at λ p = 4.8 μm and a PCSL In 0.15 Ga 0.85 As/Al 0.1 Ga 0.9 As for the LWIR detection at λ p = 10 μm. The peak responsivity for the LWIR QWIP was found to be 25 mA/W at V b = 2 V, T = 40 K, λ p = 10 μm, a FWHM of Δλ/λ p = 40%, and the calculated detectivity was found to be D* = 1.1 x 10 10 cm Hz 1/2 W -1 . Two response peaks for the MWIR QWIP were found to be at 4.8 and 5.4 μm with maximum responsivities of 12 and 19 mA/W (at T = 77 K and V b = 5 V), and spectral bandwidths of 21 and 26%, respectively. The detectivity (D*) for the MWIR stack determined at λ p = 5.4 μm, V b = 1.0 V and T = 77 K was found to be 5.5 x 10 11 cm Hz 1/2 W -1 .