High-performance mid-infrared quantum dot infrared photodetectors

Abstract

Quantum dot infrared photodetectors (QDIPs) have emerged as attractive devices for sensing long wavelength radiation. Their principle of operation is based on intersublevel transitions in quantum dots (QDs). Three-dimensional quantum confinement offers the advantages of normal incidence operation, low dark currents and high-temperature operation. The performance characteristics of mid-infrared devices with three kinds of novel heterostructures in the active region are described here. These are a device with upto 70 QD layers, a device with a superlattice in the active region, and a tunnel QDIP. Low dark currents (1.59 A cm −2 at 300 K), large responsivity (2.5 A W −1 at 78 K) and large specific detectivity (10 11 cm Hz 1/2 W −1 at 100 K) are measured in these devices. It is evident that QDIPs will find application in the design of high-temperature focal plane arrays. Imaging with small QD detector arrays using the raster scanning technique is also demonstrated.

Peculiarities of High Power Infrared Detection on Narrow-Gap Semiconductor p-n Junctions

“…Diodes with a p-n junction remain the most important infrared (IR) detectors despite numerous attempts to replace them with the Schottky barriers, multiple quantum wells and quantum dots, strain layer superlattices and alternative materials such as high temperature superconductors or pyroelectric detectors [1][2][3][4][5][6]. HgCdTe, InSb and PbTe semiconductor diodes as intrinsic detectors are widely used to cover the wavelengths of the atmospheric windows 3-5 µm and 8-14 µm [7].…”

New material systems for third generation infrared photodetectors

“…Thus, the growth and design of unique QD heterostructure is one of the most important issues related to achievement of state-of-the art QDIP performance. Figure 18 compares the highest measurable detectivities at 77 K of QDIPs found in literature [43,88,91,[94][95][96][97][98][99] with the predicted detectivities of P-on-n HgCdTe photodiodes. The solid lines are theoretical thermal limited detectivities for HgCdTe photodiodes, calculated using a 1-D model that assumes diffusion current from narrower band gap n-side is dominant.…”

“…Up till now, however, most of the QDIP devices reported in the literature have been working in the temperature range of 77 to 200 K. On account of this fact, it is interesting to insight on achievable QDIP performance in temperature range above 200 K in comparison with other type of detectors. Figure 19 compares the calculated detectivity of Auger generation-recombination limited HgCdTe photodetectors as a function of wavelength and operating temperature with the experimental of uncooled type-II InAs/GaInSb SLS detectors and QDIPs [91,98,100]. The Auger mechanism is likely to impose fundamental limitations to the LWIR HgCdTe detector performance.…”

Comparison studies of infrared photodetectors with a quantum-dot and a quantum-wire base

“…It is the main factor that determines the characteristics of QRIP, which is a measure of the signal−to−noise ratio (SNR) [19,20]. In calculating the detectivity at a certain electrical fre− quency, the output noise current at this frequency must be known.…”