Resonant cavity detectors and their materials, for spectroscopic chemical detection
Lead Research Organisation:
Lancaster University
Department Name: Physics
Abstract
The project is aiming to create and study infrared detectors for spectroscopic detection, primarily aimed at substances that require more sensitive detectors than are currently available. The detectors will be resonant cavity enhanced (a mirror is placed either side of the active layer) to improve spectral selectivity. These detectors are still in the research realm, with their demonstration yet to be achieved in some important wavelength ranges, and some open questions regarding their operation and the reconciliation of theory and experimental data. For example one important target of the project is to experimentally prove that the maximum sensitivity of resonant cavity detectors can be above the theoretical limit for standard detectors, as it is predicted to be. This has not yet been achieved.
If the project were condense to two questions they would be "can resonant cavity detectors be achieved in the short and long wave infrared" and "can their measured performance be fully reconciled with their theory, or does this need modifying".
The detectors will be modelled and designed by the student. They will grow it by molecular beam epitaxy (MBE) using InGaAsSb absorbers for short wave detectors (1.4 to 3.0 micro meters), InAsSb or super lattice absorbers for mid wave detectors (3 to 5 micro meters) and super lattice absorbers for long wave detectors (8 to 12micro meters). They will process in our cleanroom and characterise thein the lab for leakage current, spectral response and quantum efficiency in particular. The student will complete all this work, publishing their result. We expect this PhD to advance understanding in the materials used and the physical understanding of resonant cavity detectors, in particular their leakage current mechanisms. This will also by extension improve understanding of conventional detector device physics, which the resonant cavity design is attempting to push towards a limit.
EPSRC research area: photonic materials and devices
If the project were condense to two questions they would be "can resonant cavity detectors be achieved in the short and long wave infrared" and "can their measured performance be fully reconciled with their theory, or does this need modifying".
The detectors will be modelled and designed by the student. They will grow it by molecular beam epitaxy (MBE) using InGaAsSb absorbers for short wave detectors (1.4 to 3.0 micro meters), InAsSb or super lattice absorbers for mid wave detectors (3 to 5 micro meters) and super lattice absorbers for long wave detectors (8 to 12micro meters). They will process in our cleanroom and characterise thein the lab for leakage current, spectral response and quantum efficiency in particular. The student will complete all this work, publishing their result. We expect this PhD to advance understanding in the materials used and the physical understanding of resonant cavity detectors, in particular their leakage current mechanisms. This will also by extension improve understanding of conventional detector device physics, which the resonant cavity design is attempting to push towards a limit.
EPSRC research area: photonic materials and devices
Organisations
People |
ORCID iD |
| Andrew Marshall (Primary Supervisor) | |
| Andrew Bainbridge (Student) |
Studentship Projects
| Project Reference | Relationship | Related To | Start | End | Student Name |
|---|---|---|---|---|---|
| EP/R513076/1 | 01/10/2018 | 30/09/2023 | |||
| 2142954 | Studentship | EP/R513076/1 | 01/10/2018 | 31/03/2022 | Andrew Bainbridge |
| Description | Resonant cavity enhanced detectors have been demonstrated in the short-wave infrared, mid-wave infrared and long-wave infrared. Using multiple different material systems detectors which target these parts of the infrared spectrum have been fabricated and characterised. Detectors that can be targeted at different parts of the spectrum are important for the spectroscopic detection of as many different substances as possible (each substance requires detection at specific wavelengths). This work has also advanced the understanding of resonant cavity detectors and demonstrated that they can overcome the sensitivity limit that applies to conventional detectors. |
| Exploitation Route | This research provides the basis for fabrication of detectors that can target many different substances by spectroscopic detection. Detectors have been fabricated to target a few highly desirable substances as part of the research, but there are many others that would be of interest to measure spectroscopically with high sensitivity. Slight alterations in the thicknesses of the structures used in this research would allow targeting of any desired substance in these parts of the infrared spectrum. Detectors similar to the ones used in this research could be fabricated and integrated into systems to measure the concentration of specific substances, for example greenhouse gas concentrations or in-vitro biomarker concentrations. |
| Sectors | Aerospace, Defence and Marine,Pharmaceuticals and Medical Biotechnology |
| URL | https://doi.org/10.17635/lancaster/researchdata/415 |