Low-Temperature Solution-Processed Lu₂O₃ Films for Deep-UV Photovoltaic Detectors With High Sensitivity

Abstract

In this work, a low-temperature solution process is proposed to synthesize Lu 2 O 3 films with few surface defects for the purpose of fabricating high-performance deep-ultraviolet (DUV) detectors. Based on the solutionprocessed Lu 2 O 3 film treated at 250 • C, a high-sensitivity Lu 2 O 3 /GaN DUV photovoltaic detector is fabricated, which has exhibited excellent performance in many aspects. At 0 V bias voltage, it displays a peak photoresponsivity of 41.6 mA/W at 258 nm and a DUV to visible rejection ratio (R 258 nm /R 405 nm ) higher than two orders of magnitude. What's more, compared with devices based on high-temperature (500 • C) solution-processed (H-T) Lu 2 O 3 film, the device prepared in this way shows a greater photoresponsivity and a response speed faster than an order of magnitude, which can be attributed to the fewer surface defects aroused during the low-temperature solution process. The great characteristics achieved suggest the Lu 2 O 3 film treated by the method of low-temperature solution process can be applied to fabricating high-performance DUV detectors.

Solution-Processed Ga2O3 Films via Thermal Annealing for Solar Blind Ultraviolet Photovoltaic Photodetectors with High Photoresponsivity and Fast Response

“…As shown in Figure a, the photocurrent in the device increases with higher SBUV power at both the reverse and 0 V bias. Photocurrent and optical power at 0 V bias are fitted by the following equation I ph ∝ P β where I ph is the photocurrent, P the optical power, and β is the exponential factor. The fitted index of 0.97 is close to the ideal factor 1, which means the photosensitive layer (Ga 2 O 3 film annealed at 800 °C) of the device has fewer defects Figure b.…”

A high-performance Ti3C2Tx/Lu2O3/GaN heterojunction deep ultraviolet photovoltaic photodetector enhanced via the dual-field coupling effect

“…16,17 Research related to Lu 2 O 3 -based DUV PDs has gradually enriched since the first report of Lu 2 O 3 -based DUV PDs in 2021. [18][19][20][21] However, most of the Lu 2 O 3 -based DUV PDs reported currently are prone to low photoresponsivity and slow response. The unsatisfactory performance can be attributed to the low carrier separation efficiency of the device.…”

“…On the one hand, since high-quality Lu 2 O 3 single crystals are difficult to obtain, most Lu 2 O 3 single crystals mainly rely on the epitaxial growth on heterogeneous substrates. [18][19][20][21] This leads to a large number of defects induced by the lattice mismatch in Lu 2 O 3 , which will trap photogenerated carriers and reduce their separation efficiency. On the other hand, most Lu 2 O 3 -based DUV PDs only rely on a single photovoltaic effect or photoconductivity effect to separate photogenerated carriers, 19,20 resulting in a low photogenerated carrier separation efficiency.…”

“…18–21 This leads to a large number of defects induced by the lattice mismatch in Lu 2 O 3 , which will trap photogenerated carriers and reduce their separation efficiency. On the other hand, most Lu 2 O 3 -based DUV PDs only rely on a single photovoltaic effect or photoconductivity effect to separate photogenerated carriers, 19,20 resulting in a low photogenerated carrier separation efficiency.…”