Open AccessHighly reflective and conductive AlInN/GaN distributed Bragg reflectors realized by Ge-doping
Author(s) -
Cleophace Seneza,
Christoph Berger,
Prabha Sana,
Hartmut Witte,
J. Bläsing,
Anja Dempewolf,
A. Dadgar,
J. Christen,
A. Strittmatter
Publication year - 2021
Publication title -
japanese journal of applied physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 129
eISSN - 1347-4065
pISSN - 0021-4922
DOI - 10.35848/1347-4065/ac3d43
Subject(s) - materials science , optoelectronics , heterojunction , doping , epitaxy , distributed bragg reflector , resistive touchscreen , metalorganic vapour phase epitaxy , electrical conductor , optics , nanotechnology , wavelength , layer (electronics) , composite material , physics , engineering , electrical engineering
We report on the realization of highly conductive and highly reflective n-type AlInN/GaN distributed Bragg reflectors (DBR) for use in vertical cavity surface emitters in a metalorganic vapor phase epitaxy process. While Ge-doping enables low-resistive n-type GaN/AlInN/GaN heterostructures, very high Ge doping levels compromise maximum optical reflectivities of DBRs. Simulations of the Bragg mirror’s reflectivities together with structural analysis by X-ray diffraction reveal an increased absorption within the doped AlInN layers and interface roughening as major causes for the observed reduction of the optical reflectivity. By adjusting the Ge doping level in the AlInN layers, this structural degradation was minimized and highly conductive, 45-fold AlInN/GaN DBR structures with a maximum reflectivity of 99% and vertical specific resistance of 5 × 10 –4 Ω cm 2 were realized.