A voltage-tunable multicolor triple-coupled InGaAs/GaAs/AlGaAs quantum-well infrared photodetector for 8–12 μm detection

Abstract

A voltage-tunable multicolor triple-coupled quantum-well infrared photodetector (TC-QWIP) has been developed for 8–12 μm detection. The TC-QWIP consists of three coupled quantum wells formed by an enlarged Si-doped InxGa1−xAs quantum well and two undoped GaAs quantum wells separated by two thin AlyGa1−yAs barriers. Two TC-QWIP structures with varying indium and aluminum compositions were designed and demonstrated. Due to the strong coupling effect of the asymmetrical quantum wells, three bound states (E1, E2, E3) are formed inside the quantum wells of the TC-QWIP. The main detection peak wavelength is due to E1→E3 bound states transition for both devices, while two secondary detection peaks due to E1→E2 and E1→Ec continuum states transitions under different biases were also observed. In addition, a strong quantum-confined Stark shift effect for the E1→E3 transition was observed in the wavelength range of 8.2–9.1 and 10.8–11.5 μm for QWIP-A and QWIP-B, respectively; both devices exhibit a linear dependence of detection peak wavelength on the applied bias voltage. A spectral responsivity of Ri=0.05 A/W and background limited performance (BLIP) detectivity DBLIP*=6.1×109 cm√Hz/W were obtained at Vb=5 V, λp=8.6 μm, and TBLIP=66 K for QWIP-A, while Ri=0.33 A/W and DBLIP* =1.63×1010 cm√Hz/W at Vb=4 V, λp=11.2 μm, and TBLIP=50 K were obtained for QWIP-B.

Photonic Crystal/Nano-Electronic Device Structures for Large Array Thermal Imaging

“…The existing designs suffer from limited range of tunability and substantial spectral cross-talk [1][2][3][4][5][6]. We therefore solved these problems and developed the world's first semiconductor four-color QWIP which demonstrated four distinct narrowband peaks without spectral cross-talk in a single device.…”

A two-stack, multi-color In0.5Ga0.5As/GaAs and lnAs/GaAs quantum dot infrared photodetector for long wavelength infrared detection

“…The two-, three-and four-color quantum well infrared photodetectors (QWIPs) for detection in the middle-, long-, and very long-wavelength regions have been reported, with the peak detectivities in the range of 10 10 -10 12 cm Hz 1=2 /W for T 6 77 K [15][16][17][18][19][20]. These multi-color QWIPs are realized by several structures, including the multistack structure with each stack detecting different wavebands [15,16], or using asymmetrical multiquantum well structure with tunable wavelength by the applied bias voltage [17]. Theoretically, QDIPs have the potential for higher photoresponse to infrared radiation and higher operation temperature than QWIPs due to the longer carrier capture and relaxation times.…”

Electro-absorption and electro-refraction in Ge/SiGe coupled quantum wells

“…Symmetrically and asymmetrically CQW exhibit a peculiar physical behavior due to the coupling of the wavefunctions through the barrier 18 . For this reason, they were widely investigated in III-V semiconductors for many purposes including non-linear optics 19 , photodetection 20 and optical modulation 21 . In this work, electro-absorption (EA) and ER have been investigated in Ge/Si 0.15 Ge 0.85 CQWs by means of optical transmission measurements.…”