Related Experiment Video
Updated: Sep 21, 2025
08:48
Writing Bragg Gratings in Multicore Fibers
Published on: April 20, 2016
8.3K
Nearly Lattice-Matched GaN Distributed Bragg Reflectors with Enhanced Performance
Ye Tian1, Peng Feng1, Chenqi Zhu1
1Department of Electronic and Electrical Engineering, The University of Sheffield, Sheffield S1 3JD, UK.
Materials (Basel, Switzerland)
|May 28, 2022
Summary
This study introduces a novel approach for fabricating distributed Bragg reflectors (DBRs) using silicon-doped aluminum gallium nitride (AlGaN) and gallium nitride (GaN). The new method results in smoother surfaces, higher reflectivity, and wider stopbands compared to traditional GaN-based DBRs.
Area of Science:
- Materials Science
- Optoelectronics
- Semiconductor Physics
Background:
- Heavy silicon-doping in GaN typically leads to surface roughness and saturated conductivity.
- Heavily silicon-doped n++-AlGaN with low aluminum content offers an atomically flat surface and enhanced conductivity, presenting a significant advantage over GaN.
Purpose of the Study:
- To propose and demonstrate a novel lattice-matched distributed Bragg reflector (DBR) using multiple pairs of heavily silicon-doped n++-Al0.01Ga0.99N and undoped GaN.
- To leverage electrochemical (EC) etching to convert n++-layers into nanoporous (NP) layers, creating a high refractive index contrast for DBR formation.
- To compare the performance of the proposed NP-Al0.01Ga0.99N/undoped GaN DBR with traditional NP-GaN/undoped GaN DBRs.
Main Methods:
- Fabrication of DBRs using multiple pairs of heavily silicon-doped n++-Al0.01Ga0.99N and undoped GaN.
- Application of electrochemical (EC) etching to convert n++-Al0.01Ga0.99N layers into nanoporous (NP) Al0.01Ga0.99N layers.
- Characterization of DBR properties including surface morphology, reflectivity, stopband width, and sample size.
Main Results:
- The NP-Al0.01Ga0.99N/undoped GaN DBR exhibits a significantly smoother surface compared to NP-GaN/undoped GaN DBRs.
- Enhanced reflectivity and a wider stopband were observed for the NP-Al0.01Ga0.99N/undoped GaN DBR.
- Large-sized DBR samples (up to 1 mm width) were successfully fabricated using the proposed method, surpassing the typical size limitations of conventional DBRs.
- Demonstrated high-performance DBR structures with tunable optical properties from blue to dark yellow.
Conclusions:
- The use of heavily silicon-doped n++-Al0.01Ga0.99N offers a superior alternative to n++-GaN for fabricating high-performance DBRs.
- Electrochemical etching provides an effective method for creating nanoporous layers with high refractive index contrast, essential for DBRs.
- The developed NP-Al0.01Ga0.99N/undoped GaN DBR technology enables the fabrication of larger, smoother, and more efficient optical devices.
