Zhao, YunlongYunlongZhaoWan, ZeyuZeyuWanGuo, JiaJiaGuoYang, YunchengYunchengYangCheng, Hao TienHao TienChengChrostowski, LukasLukasChrostowskiLackner, DavidDavidLacknerWu, Chao Hsin WayneChao Hsin WayneWuXia, Guangrui (Maggie)Guangrui (Maggie)Xia2026-03-132026-03-132024https://publica.fraunhofer.de/handle/publica/50973410.1109/LPT.2023.33443552-s2.0-85181586146High-quality n-type AlGaAs distributed Bragg reflectors (DBRs) and lnGaAs multiple quantum wells (MQWs) were successfully monolithically grown on 4-inch off-cut Ge (100) wafers. Even without any design and process optimization for the Ge substrates, the Ge-based half VCSELs have photoluminescence and reflectance spectra comparable to those grown on conventional GaAs wafers. Flat and sub-nm RMS surface roughness and uniform DBR and MQW growth across the wafer were achieved. These results strongly support full VCSEL growth and fabrication on larger-area Ge wafers for the mass production of AlGaAs-based VCSELs.entrueDistributed Bragg reflector (DBR)growth qualityoptical performancereflectancestopbandvertical cavity surface emitting laser (VCSEL)journal article