“…β-Ga 2 O 3 , an intrinsic n-type semiconductor with an ultrawide bandgap (∼4.9 eV), is considered to be an ideal candidate for preparing SBUV PDs. , During the growth of β-Ga 2 O 3 , the easily formed oxygen vacancies are usually considered as the cause for the n-type characteristics of β-Ga 2 O 3 . , However, oxygen vacancies are prone to form photoacoustic carrier trapping centers; thus, most of the previously reported Ga 2 O 3 -based PDs exhibit slow response speed and low photoresponsivity. , Actually, the method of acceptor impurity doping has been proven to be effective in reducing oxygen vacancies in heteroepitaxial films. , However, as a result of inappropriate growth scheme designs, most of the reported acceptor impurities doped Ga 2 O 3 films present polycrystalline, mixed crystal, and amorphous structures. − Compared with single crystal orientation Ga 2 O 3 films, those films exhibit more grain boundaries, which lead to an increased probability of carriers being trapped or scattered. ,− Therefore, the photoresponsivity of the PDs based on these films is relatively low. − , …”