Optical coupling design of quantum dot infrared photodetectors

Background:
There is a growing market for cameras that detect infrared radiation, with applications in night vision, space, surveillance, search and rescue and medical diagnosis. More stringent requirements for the cameras, such as higher operating temperature, create a demand for detectors that use more advanced materials. Suitable candidates are quantum dot infrared photodetectors (QDIPs), which are expected to significantly increase the performance and lower cost.
Acreo is developing QDIPs and test components have been fabricated. However, these QDIP structures have not been optimised regarding optical coupling. Enhanced optical coupling is expected to significantly increase the absorption in the structure and consequently also the responsivity.
In this study, different ways of enhancing the optical coupling will be studied. Simulations in FEMLAB will be performed in order to find the best solution for optical coupling in QDIPs.

Goal:
To make a comparative study of different designs for optical coupling in QDIPs through simulations in FEMLAB.

Description:
The following tasks will be conducted in the frame of the diploma work project:

1. Literature studies on absorption in quantum dots and optical coupling structures
2. Modelling of the absorption properties of quantum dots and modification of an existing FEMLAB program to the chosen optical coupling structures.
3. Simulations in FEMLAB to find an optimal optical coupling structure
4. Written report