Proceedings of Materials for Sustainable Development Conference (MAT-SUS) (NFM22)
Publication date: 11th July 2022
In recent years, hybrid organic-inorganic perovskites (HOIPs), particularly those of general formula ABX3 (A = organic cation; B = Pb; X = halide) have emerged as one the most promising groups of semiconductors due to their unprecedented optical properties combined with facile processing. Among HOIPs CH3NH3PbI3 (MAPI) revealed its excellent properties for solar absorber (1.55 eV direct band gap, small exciton binding energy, long charge carrier diffusion length, high charge carrier mobilities) becoming the most famous and extensively studied hybrid halide perovskite [1].
But looking at the noble establishment of semiconductor materials, the representative of III-V, GaN, is still on the table, since after 30 brilliant years career in (opto)electronics (LEDs, lasers, photodetectors, HEMT and power devices) is up to now an attractive subject of studies, particularly in combination with emerging materials as van der Waals crystals or perovskites. Specifically, devices as light emitters [2], solar cells [3,4] and photodetectors [5,6] can be evoked as examples. In this context, the understanding of interfacial electronic phenomena has to be provided.
In this study we present the investigation of MAPI/GaN interface by means of contactless electroreflectance spectroscopy (CER), which enables precise determination of the Fermi level position at the interface and thus enables to conclude about the carrier transport through it. We observed the increase of surface barrier height for MAPI/GaN interface comparing to reference GaN surface, what can be translated to the carrier flow from GaN surface to MAPI. Additionally, we demonstrate the prototype of fast, self-powered MAPI/GaN based photodetector operating in a broad spectral range.