Abstract
The development of advanced compound semiconductors is at the forefront of technological innovation enabling improved and new device functionalities for a range of photonics applications. In this thesis, two advanced III-V heterostructure systems based on GaSb alloys are developed for emerging light emitting applications. The first part of this thesis covers the development of GaSbBi epitaxy and investigation of its unique material properties. The motivation here is to enable more advanced band gap engineering capability for type-I quantum well (QW) heterostructures. The second part of this thesis covers the development of local droplet etching (LDE) process in the GaSb-system enabling the fabrication of high- quality quantum dots (QDs). This work is positioned in the field of rapid innovation of addressing the need for non-classical light sources for quantum technology systems operating at telecommunication wavelengths around 1.5 µm. Proof-of- concept devices for both materials systems are demonstrated. For GaSbBi, an edge-emitting laser diode and a saturable absorber mirror utilizing GaSbBi QWs operating at around 2.1 µm wavelength are demonstrated. For GaSb QDs, a single-photon source emitting at 1.47 µm wavelength (telecom S-band) is demonstrated for the first time.
The main findings of this work expands over three categories: (i) epitaxial processes, (ii) physical properties of semiconductor heterostructures, and (iii) proof-of-concept devices. The optimal growth parameter space for GaSbBi is identified and a maximum Bi incorporation of ~15%Bi is demonstrated while maintaining moderate structural quality. The investigated properties and performance of devices indicate that material quality of GaSbBi is likely hindered by defects. Regarding GaSb QDs, the LDE process is shown to work extremely well for the antimonide system with a high degree of control and tunability. The fabricated QDs exhibit state-of-the-art uniformity in emission wavelength. Moreover, the single QD emission properties are very promising in terms of narrow excitonic emission, single-photon emission purity, and low QD asymmetry. However, room for further optimization exists concerning the QD geometry and composition, as well as for integration into quantum photonic systems.
The main findings of this work expands over three categories: (i) epitaxial processes, (ii) physical properties of semiconductor heterostructures, and (iii) proof-of-concept devices. The optimal growth parameter space for GaSbBi is identified and a maximum Bi incorporation of ~15%Bi is demonstrated while maintaining moderate structural quality. The investigated properties and performance of devices indicate that material quality of GaSbBi is likely hindered by defects. Regarding GaSb QDs, the LDE process is shown to work extremely well for the antimonide system with a high degree of control and tunability. The fabricated QDs exhibit state-of-the-art uniformity in emission wavelength. Moreover, the single QD emission properties are very promising in terms of narrow excitonic emission, single-photon emission purity, and low QD asymmetry. However, room for further optimization exists concerning the QD geometry and composition, as well as for integration into quantum photonic systems.
| Original language | English |
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| Place of Publication | Tampere |
| Publisher | Tampere University |
| ISBN (Electronic) | 978-952-03-3703-2 |
| ISBN (Print) | 978-952-03-3702-5 |
| Publication status | Published - 2024 |
| Publication type | G5 Doctoral dissertation (articles) |
Publication series
| Name | Tampere University Dissertations - Tampereen yliopiston väitöskirjat |
|---|---|
| Volume | 1138 |
| ISSN (Print) | 2489-9860 |
| ISSN (Electronic) | 2490-0028 |