Dresden 2020 – wissenschaftliches Programm
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HL 30.27: Poster
Dienstag, 17. März 2020, 13:30–15:45, P3
Highly reflective and conductive AlInN/GaN distributed Bragg reflectors realized by Ge-doping — •Cleophace Seneza, Christoph Berger, Hartmut Witte, Jürgen Bläsing, Anja Dempewolf, Armin Dadgar, Jürgen Christen, and André Strittmatter — Otto-von-Guericke-University Magdeburg, 39106 Magdeburg, Germany
Lattice-matched AlInN has been proven as well-suited material to realize highly reflective AlInN/GaN distributed Bragg reflectors (DBRs), which are mandatory for the fabrication of vertical-cavity surface-emitting lasers (VCSELs) using GaN-based material. In contrast to GaAs-VCSELs with highly conductive arsenide-based DBRs, AlInN/GaN-based DBRs usually exhibit high electrical resistance due to large polarization fields and a significant conduction band offset between GaN and AlInN. Therefore, intracavity contacts are employed for VCSELs to inject current into the active region. We demonstrate that Ge can be used as n-type donor to realize low-resistive lattice-matched AlInN/GaN DBRs. Various Ge-doping levels were utilized to study the vertical electrical conductivity and reflectance properties of lattice-matched AlInN/GaN DBRs grown by MOVPE. We will present the effect of Ge-doping on structural properties, electrical and optical properties of DBRs. With Ge-doping, lattice-matched AlInN/GaN DBRs exhibit ohmic behavior and high reflectivity. Such DBRs structures have a huge potential to improve the current-injection, lower the threshold-current density and will also help to simplify the fabrication processes for VCSELs.