Growth of InAs/GaSb Type-II superlattice infrared photodetector structures on GaSb and GaAs substrates by MBE technique

In this thesis, epitaxial growth of InAs/GaSb Type-II superlattice photodetector structures that are prominent in the new generation infrared detector technology for their high performance and high temperature applications in mid and long wavelength infrared regions was carried out by using molecular beam epitaxy on 2 inch GaSb and 4 inch GaAs substrates. Structural properties of the grown superlattice samples have been investigated by high resolution X-ray diffraction and transmission electron microscopy analysis. Electrical properties and optical performances have also been investigated through measurements on the fabricated single pixel photodetectors. Groups of samples where the thickness of the individual InAs and GaSb layers that forms the superlattice and the transition interfaces between these layers are systematically changed were grown and their opto-electronic characterizations have been completed. Identical structures grown on both GaSb substrates that are advantageous for their crystal lattice matching and GaAs substrate that are advantageous for their bigger size, high crystal quality, low cost and dopant free producibility despite their lattice mismatch were comparatively evaluated. Similar detector performances were obtained from the samples grown on GaAs substrate with especially AlSb quantum dots as interface layer between the GaAs substrate and GaSb epilayer. Thus, it was shown that the GaAs substrates are alternative to GaSb for InAs/GaSb superlattice material system.