Three-color (λp1∼3.8 μm, λp2∼8.5 μm, and λp3∼23.2 μm) InAs/InGaAs quantum-dots-in-a-well detector

Abstract

We report a three-color InAs/InGaAs quantum-dots-in-a-well detector with center wavelengths at ∼3.8, ∼8.5, and ∼23.2 μm. We believe that the shorter wavelength responses (3.8 and 8.5 μm) are due to bound-to-continuum and bound-to-bound transitions between the states in the dot and states in the well, whereas the longer wavelength response (23.2 μm) is due to intersubband transition between dot levels. A bias-dependent activation energy ∼100 meV was extracted from the Arrhenius plots of the dark currents, which is a factor of 3 larger than that observed in quantum-well infrared photodetectors operating at comparable wavelengths.

Optical pumping as artificial doping in quantum dots-in-a-well infrared photodetectors

“…6 Several groups have even reported response in the far infrared region ͑Ͼ20 m͒ emanating from transitions between different bound QD states. 7,8 However, a detailed understanding of all relevant transitions occurring in the detector has not yet been achieved. This knowledge is essential in order to design and optimize a high performance infrared detector.…”

Versatile Spectral Imaging With an Algorithm-Based Spectrometer Using Highly Tuneable Quantum Dot Infrared Photodetectors

“…However the wavelength range covered is usually small and hence is not ideal for the system described above, although in principle different quantum well designs can be adopted to yield the desired spectral characteristics. By incorporating M quantum dots in the quantum wells, dot-in-a-well (DWELL) quantum dot infrared photodetectors (QDIPs) can be designed to exhibit a spectral response that can be tuned across a wide wavelength range [8], [9], as well as providing normal incidence detection. The spectral response of these detectors will vary as a function of the bias voltage applied across the detector allowing one QDIP to effectively act as several separate detectors with differing spectral responses.…”

Quantum structures for multiband photon detection

“…From photoluminescence measurements of the ground state transition of the dot (1.25 µm at T = 300 K) and using a 60:40 conduction: valence band ratio, it is estimated that the ground state of the dot is about 250 meV below the GaAs band edge. There can be at least two bound states in the dot and one confined state in the quantum well [11], as shown in Fig. 1(b).…”

“…While recently reported dual band [1,[23][24][25] and multiband [5,11,26,27] detectors can detect near-infrared (NIR), mid-infrared (MIR), and far-infrared (FIR) radiation, the HIWIP and HEIWIP detectors have the ability to detect a much wider range of photons, even covering the UV and FIR bands in a single structure. Both HIWIP and HEIWIP detectors [21,22] were studied as FIR detectors.…”