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

Abstract

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.

Effects of high energy proton implantation on the optical and electrical properties of In(Ga)as/GaAs QD heterostructures with variations in the capping layer

“…Our study showed that a quaternary InAlGaAs capping always achieved better dot quality; therefore, we used it as the capping layer of the InGaAs/GaAs QDIP structure for the electrical study (Fig. 2) [26]. The QDIP heterostructure was implanted with a stable beam of 3 MeV protons at a fluence of 2.0 Â 10 12 ions/cm 2 .…”

“…10). We believe that the dot size within the QDIP increased because of proton implantation [26]. TRIM calculations [27] show that during implantation, ions are subjected to electronic and nuclear energy losses.…”

“…2) with the same epitaxial technique on a semi-insulating GaAs substrate (100) [26]. A growth rate of approximately 0.22 ML/s was maintained to grow 7 ML InGaAs dots at 500 1C throughout the 10-layer heterostructure.…”

“…Recognizing the quality improvement of InAs dots through low energy H À ion implantation, Mandal et al validated these results for In(Ga)As/GaAs QDIPs. Low energy H À ion implantation suppressed the dark current density for In(Ga)As/ GaAs QDIPs [25,26], enhanced their multi-color spectral response, and increased their peak detectivity by more than one order [26]. In this study, we examine the effects of high energy proton implantation on the optical and material qualities of InAs dots capped with both GaAs and InAlGaAs layers.…”

InAs/GaAs p – i – p quantum dots‐in‐a‐well infrared photodetectors operating beyond 200 K

“…In particular, InAs/GaAs QDIPs have been extensively investigated due to their advantageous properties, such as sensitivity to normal incident infrared radiation and weak thermionic coupling between the ground state and excited states, compared to quantum well IPs (QWIPs), resulting in reduced dark current. In the past few years, the intersubband photoresponse of n-type QD detector structures have been the subject of intense research [3][4][5][6]. However, high-temperature operation of n-type QDIPs has still remained a challenging problem although the hydrogenbased treatment processes were conducted to suppress the dark current [5,6].…”