Towards a European supply chain for type-II superlattice infrared detectors.

Purpose and goal:

The purpose of this project was to investigate growth techniques of GaSb on Si substrate by MOCVD (Metal Organic Chemical Vapor Deposition) to secure EU supply of substrates for T2SL IR detectors. Successful homoepitaxial growth was demonstrated with good surface morphology, showing sub-nanometer roughness and visible atomics steps. Promising initial results were also obtained in GaSb-on-GaAs and GaSb-on-GaAs-on-Si growths, which provides a good starting point for further optimizations in planned follow-on projects.

Expected results and effects:

While more challenging than anticipated, our studies on homoepitaxy enabled us to achieve good surface morphology which resulted in the standardization of growth conditions of GaSb. Though further optimizations are needed, the investigations led on heteroepitaxy on GaAs and Si allowed us to acquire knowledge and establish methodology which will be used in follow-up projects. Ultimately, the expected impact is a secure EU supply of GaSb substrate and larger volume production T2SL IR detectors.

Approach and implementation:

The work has been performed in close collaboration between IRnova and KTH. While IRnova was responsible for the literature survey on the MOCVD growth of GaSb and T2SL on GaSb and non-native substrates and, the formation of a reference group for a potential EU project, KTH performed all the growths and material characterizations. Both partners commonly supervised a master student who was involved in the project who will continue this work in an industrial PhD project starting January 2025.