Fig. 6

Back-to-back MSM photodiodes based on c-BN and AlN. a SEM image of the cross-sectional morphology of the c-BN/diamond composite film [95]. b In the range of 175–250 nm and under the irradiation of DUV monochrome light source, spectral responsivity of c-BN MSM photodiodes respectively measured at bias voltages of − 20, − 30 and − 35 V [95]. c Schematic representation of the AlN device layer structure [96]. d Cross-sectional diagram of MSM-AlN detector structure in the proton damage test [97]. e Signal stability test of MSM-AlN-017 (room temperature) at a power level of about 0.17 μA 121.6 nm and under + 15 V and + 25 V bias. The illustration presents a close-up view (linear scale) to show the improved stability of the detector at + 25 V [97]. f Spectral responsivity of MSM-AlN-008 (2 mm in diameter) within the wavelength between 190 and 700 nm before and after proton irradiation of 1 × 10¹¹p⁺/cm² [97]