Broadband Photodetector for Ultraviolet to Visible Wavelengths Based on the BA2PbI4/GaN Heterostructure.

Two-dimensional (2D) organic-inorganic hybrid perovskites (OIPs) have exhibited ideal prospects for perovskite photodetectors (PDs) owing to their remarkable environmental stability, tunable band gap, and structural diversity. However, most perovskites face the great challenge of a narrow spectral response. Integrating 2D OIPs with a suitable wide band gap semiconductor gives opportunities to broaden the response spectra. Here, a photodetector based on the BA2PbI4/GaN heterostructure with a broadband photoresponse covering from the ultraviolet (UV) to visible band is designed. We demonstrate that the device is capable of detecting in the UV region by p-GaN being integrated with BA2PbI4. The morphology and material optical properties of BA2PbI4 are characterized by transmission electron microscopy (TEM) and photoluminescence (PL). Additionally, the current-voltage (I-V) characteristics and photoresponses of the BA2PbI4/GaN heterojunction photodetector are investigated. The response spectrum of the photodetector is broadened from the visible to UV region, exhibiting good rectifying behavior in the dark conditions and a broadband photoresponse from the UV to the visible region. Additionally, the energy band is used to analyze the current mechanism of the BA2PbI4/GaN heterojunction PD. This study is expected to provide a new insight of optoelectronic devices by integrating 2D OIPs such as BA2PbI4 and wide-band-gap semiconductors such as GaN to broaden the response spectra.