A novel Pt modified AlGaN/Si double-junction nanostructure for stable and self-powered solar blind photoelectrochemical photodetection

Abstract

Simultaneously searching for self-powered, efficient, stable photoelectrode is the key to realizing the next-generation energy-efficient and sustainable integrated solar blind photoelectrochemical (PEC) photodetector. In this work, a Pt modified AlGaN/Si double-junction nanostructure with an n++ AlGaN/p++ AlGaN tunnel junction (TJ) and a AlGaN/Si junction is reported to achieve stable and self-powered solar blind photodetection. PEC tests demonstrate that the photocurrent density of the Pt modified AlGaN with n++ AlGaN/p++ AlGaN TJ photoelectrode can reach up to −56.1 μA/cm2 under 255 nm light irradiation with 1.1 mW/cm2 at 0 V bias versus a Pt counter electrode in a three-electrode configuration. Time-steady photoluminescence and XRD spectra are carried out and confirm the inherent optical and physical properties of this nanostructure. In addition, the multicycle and long-term stability measurement shows an excellent switching behavior even after being placed in the air for one month with a photocurrent density of −44.9 μA/cm2 (80% of its initial photocurrent). Furthermore, the PEC performance of the Pt modified AlGaN with n++ AlGaN/p++ AlGaN tunnel junction photoelectrode is evaluated in different light wavelengths, light intensities, bias potential and H2SO4 concentrations. These results demonstrate that the as-prepared photoelectrode has a great potential application in stable self-powered solar blind photodetector.