Photoluminescence from Defects in Be‐Doped GaN

While GaN is a crucial semiconductor material for bright light‐emitting devices, fabrication of p‐type GaN remains challenging since the Mg acceptor commonly used for p‐type doping is not shallow enough. Doping of GaN with Be is a promising path, yet no reliable p‐type GaN has been achieved by Be doping so far. One of the reasons is a poor understanding of point defects in Be‐doped GaN that can be studied by photoluminescence (PL). The yellow (YL Be ) band at 2.15 eV is the dominant PL band in Be‐doped GaN. In this work, a blue PL band named the BL Be band is discovered. It has a maximum at 2.6 eV and a lifetime of 0.8 μs at temperatures below 100 K. The BL Be band is observed in GaN samples with relatively high concentrations of Be (>10 18 cm −3 ). Both the YL Be and BL Be bands likely originate from the isolated Be Ga defect, namely from electron transitions via the −/0 and 0/+ thermodynamic transition levels of the Be Ga . The 0/+ transition level is located at 0.1–0.2 eV above the valence band. Other broad PL bands in Be‐doped GaN were also observed and preliminarily attributed to Be‐containing complexes.