Ferroelectric enhanced GaO/BFMO-based deep ultraviolet photovoltaic detectors with dual electric fields for photogenerated carrier separation

Ga 2 O 3 -based photovoltaic-type ( i.e. , self-driven) deep ultraviolet (DUV) photodetectors have attracted extensive attention due to their broad application prospects in civilian and military fields. However, their common drawback of poor light sensitivity ( i.e. , responsivity and detectivity) has greatly hindered their practical applications. In this work, we propose a strategy for constructing a Ga 2 O 3 /BiFe 0.95 Mn 0.05 O 3 (BFMO) ferroelectric/semiconductor heterojunction-based photodetector with higher responsivity and detectivity than single BFMO and single Ga 2 O 3 devices by exploiting the built-in electric field at the Ga 2 O 3 /BFMO heterojunction interface ( E Ga 2 O 3 /BFMO ) and the ferroelectric depolarization electric field across the BFMO ( E dp ) to promote the separation of photogenerated carriers. The fabricated Ga 2 O 3 /BFMO heterojunction photodetector exhibits tunable performance under zero bias. Higher responsivity (19.01 mA W −1 @ 260 nm) and detectivity (4.52 × 10 11 Jones @ 260 nm) are observed for the photodetector in the upward poling state than that in the unpoled state, which can be attributed to the coupling effect of E dp and E Ga 2 O 3 /BFMO . Moreover, the photodetector shows even higher responsivity (23.54 mA W −1 ) and detectivity (5.58 × 10 11 Jones) under weak light illumination ( P 260nm = 0.002 mW cm −2 ), with values much higher than those reported for Ga 2 O 3 -based heterojunction photodetectors. This work offers an effective approach for boosting the performance of self-driven UV photodetectors. A high-performance self-driven deep UV photodetector based on a Ga 2 O 3 /BFMO heterojunction is developed by utilizing E Ga 2 O 3 /BFMO and E dp to simultaneously separate photogenerated carriers.