Performance Of Quantum Dot Infrared Photodetectors Research Articles

Enhancement in multicolor photoresponse for quaternary capped In0.5Ga0.5As/GaAs quantum dot infrared photodetectors implanted with hydrogen ions

In(Ga)As/GaAs-based quantum dot infrared photodetectors (QDIPs) are among the most efficient devices in the mid-wavelength infrared and long-wavelength infrared regions for various defense and space application purposes. Considering the importance of the results reported so far on In(Ga)As/GaAs QDIPs, here we had tried to develop a post-growth method for enhancing QDIP characteristics using both low energy and high energy light ion (hydrogen) implantations. The field-assisted tunneling process of dark current generation was suppressed due to the hydrogen ion implantation, even at a very high operational bias. A stronger multicolor photo-response was obtained for devices implanted with low energy hydrogen ions. From experimental results, we proposed a device model which explains the improved QDIPs performance caused by hydrogen ion implantation.

More than one order enhancement in peak detectivity (D*) for quantum dot infrared photodetectors implanted with low energy light ions (H−)

In(Ga)As/GaAs-based quantum dot infrared photodetectors (QDIPs) have emerged as one of the most suitable devices for infrared detection. However, quantum dot devices suffer from lower efficiencies due to a low fill-factor (∼20%–25%) of dots. Here, we report a post-growth technique for improving the QDIP performance using low energy light ion (H−) implantation. At high bias, there is evidence of suppression in the field-assisted tunneling component of the dark current. Enhancement in peak detectivity (D*), a measure of the signal-to-noise ratio, by more than one order, from ∼109 to 2.44 × 1010 cm Hz1/2/W was obtained from the implanted devices.

Review of current progress in quantum dot infrared photodetectors

AbstractQuantum dot infrared photodetectors (QDIPs) have made significant progress after their early demonstration about a decade ago. We review the progress made by QDIP technology over the last few years and compare QDIPs with quantum well infrared photodetectors (QWIPs). It is shown that the performance of QDIPs has significantly improved using novel architectures such as dots‐in‐a‐well designs, and large‐format (1 K × 1 K) focal plane arrays have been realized. However, even though there are significant reports of performance parameters better than QWIPs from single‐pixel devices, QDIP‐based focal plane arrays are still a factor of 3–5 worse in terms of noise equivalent temperature difference. We discuss the reasons for the performance gap and the key scientific and technological challenges that need to be addressed to achieve the full potential of QD‐based technology.

Outlook on quantum dot infrared photodetectors

This paper reviews the present status and gives outlook on future developments of quantum dot infrared photodetectors (QDIPs). At the beginning the paper summarizes the fundamental properties of QDIPs. Next, an emphasize is put on their potential developments. Investigations of the performance of QDIPs as compared to other types of infrared photodetectors are presented. A model is based on fundamental performance limitations enabling a direct comparison between different infrared material technologies. It is assumed that the performance is due to thermal generation in the active detector’s region. In comparative studies, the HgCdTe photodiodes, quantum well infrared photodetectors (QWIPs), type II superllatice photodiodes, Schottky barrier photoemissive detectors, doped silicon detectors, and high temperature superconductor detectors are considered.

Insight on quantum dot infrared photodetectors

The paper presents possible future developments of quantum dot infrared photodetectors (QDIPs). At the beginning the fundamental properties of QDIPs are summarized. Next, investigations of the performance of QDIPs, as compared to other types of infrared photodetectors, are presented. Theoretical predictions indicate that only type II superlattice photodiodes and QDIPs are expected to compete with HgCdTe photodiodes. QDIPs theoretically have several advantages compared with QWIPs including the normal incidence response, lower dark current, higher operating temperature, higher responsivity and detectivity. The operating temperature for HgCdTe detectors is higher than for other types of photon detectors. Comparison of QDIP performance with HgCdTe detectors gives evidence that the QDIP is suitable for high operation temperature. It can be expected that an improvement in technology and design of QDIP detectors will make it possible to achieve both high sensitivity and fast response useful for practical application at room temperature focal plane arrays. However, so far the QDIP devices have not fully demonstrated their potential advantages.

Assessment of quantum dot infrared photodetectors for high temperature operation

Investigation of the performance of quantum dot infrared photodetectors (QDIPs) in comparison to other types of infrared photodetectors operated near room temperature is presented. The model is based on fundamental performance limitations enabling a direct comparison between different infrared material technologies. It is assumed that the performance is due to thermal generation in the active region. Theoretical estimations provide evidence that the QDIP is suitable for noncryogenic operation especially in long-wavelength infrared region, where conventional HgCdTe photodiodes are not viable. Hence it is expected that improvement in technology and design of QDIP detectors will make it useful for practical application. The higher operating speed of QDIP and multispectral capability are considerable advantages in comparison with thermal detectors. Comparison of theoretically predicted and experimental data indicates that, as so far, the QDIP devices have not demonstrated their potential advantages and are expected to posses the fundamental ability to achieve higher detector performance. Poor QDIP performance is generally linked to nonoptimal band structure and control over the QDs size and density.

Quantum-Dot Infrared Photodetectors

We present a study of a series of n-i-n InAs quantum-dot infrared photodetectors (QDIPs) with unintentionally doped active regions. Different quantum-dot capping layer materials (GaAs, InGaAs, and AlGaAs) are utilized to tune the operating wavelength and modify the QDIP performance. Normal-incidence operation with high detectivity in the mid (3-5 ) and long (8-12 ) wavelength regimes and the potential for multicolor operation is demonstrated.

High-performance 30-period quantum-dot infrared photodetector

In this article, quantum-dot infrared photodetectors (QDIPs) with 10- and 30-period InAs∕GaAs quantum-dot structures are investigated. High responsivity of 2.37A∕W and detectivity of 2.48×1010cmHz1∕2∕W for 30-period QDIPs under 10K are observed at −2.7 and 1.2V, respectively. Almost symmetric photocurrents and dark currents under positive and negative biases are observed for both devices, which indicate a minor influence of the wetting layer on the performance of QDIPs. Lower dark current and increased photocurrent for the 30-period QDIPs would predict a better performance for devices with over a 30-period QD structure.

Normal-incidence far-infrared detectivity of InAs/GaAs QDIPs doped in dots and barriers

Abstract We report some comparative results on the normal-incidence device characteristics accomplished with a couple of self-assembled InAs/GaAs quantum-dot infrared photodetectors (QDIPs) doped in InAs QDs and GaAs barriers. The peak values of responsivity and detectivity for the barrier-doped device are 650 mA/W and 3.2 × 108 cm Hz1/2/W (18 K) at λp ≅ 5 μm, respectively, which are approximately two and ten times higher than those for the QD-doped one. In addition, while there is no spectral response over 6 μm in the QD-doped structure, a strong photoresponse is extended up to around 10 μm in the barrier-doped one. Although the direct doping in InAs QDs is effective for blocking the dark current, the doping in GaAs barriers has better device performance of QDIP.

On the detectivity of quantum-dot infrared photodetectors

We report on the analysis of thermally-limited operation of quantum-dot infrared photodetectors (QDIPs). A device model is developed and used to calculate the QDIP detectivity as a function of the structural parameters, temperature, and applied voltage, as well as to determine the conditions for the detectivity maximum. The QDIP detectivity is compared with that of quantum-well infrared photodetectors (QWIPs). This work clarifies why the existing QDIPs are still inferior to QWIPs and shows that a significant improvement in the QDIP performance can be accomplished by the utilization of dense QD arrays with small QDs.