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  • 2020DelliPhD

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Monolithic integration of mid-infrared III-V semiconductor materials and devices onto silicon

Research output: ThesisDoctoral Thesis

Publication date03/2020
Number of pages250
Awarding Institution
Thesis sponsors
  • Engineering and Physical Sciences Research Council
  • Royal Academy of Engineering
  • Joy Welch Educational Charitable Trust
  • Lancaster University - Research Committee
Award date29/02/2020
  • Lancaster University
<mark>Original language</mark>English


Monolithic integration of antimonide (Sb) based semiconductors with silicon (Si) holds the potential for creating a new research area in mid-infrared (MIR) silicon photonics. This would impact over many fields including environmental monitoring, industrial process control, bio-medicine and homeland security. However, the significant material dissimilarities between III-V semiconductors and Si result in various crystal imperfections making direct epitaxial growth extremely difficult. This thesis reports on the development of new techniques to grow GaSb-based materials and devices directly onto Si wafers using molecular beam epitaxy (MBE). To begin with, a novel technique was developed using an efficient AlSb interfacial misfit array (IMF) combined with a two-temperature growth procedure to create a GaSb buffer layer. This was free of antiphase domains and exhibited a surface dislocation density of 2 x 108 cm-2. Next, GaSb-based dislocation filter superlattice (DFSL) structures were developed to further improve the material quality which resulted in a surface defect density as low as 6 x 106 cm-2. MIR InAsSb light emitting diodes were fabricated on Si using the two-step GaSb buffer layer which exhibited bright electroluminescence at room temperature peaking at around 4.5 μm. A new growth strategy was also developed to grow InAs layers on Si using the two-step GaSb buffer. Subsequently high crystalline quality InAsSb/InAs/Si multi-quantum wells were grown which demonstrated bright photoluminescence up to 300 K. Finally, a high performance type-II InAs/InAsSb superlattice barrier photodetector was grown on Si using a GaSb/AlSb DFSL structure. The device exhibited an extended MIR 50 % cut-off wavelength at around 5.2 µm and a maximum specific detectivity of 3.65 x 1010 Jones at 160 K.