Optics and Laser Technology, cilt.190, 2025 (SCI-Expanded, Scopus)
In this study, the negative capacitance (NC) phenomena is investigated in a GaInNAs/GaNAs-based bidirectional multi-quantum well p-i-n junction device designed for both light-emitting diode (LED) and photodetector, for near-infrared telecom applications. The device was grown by molecular beam epitaxy (MBE) with a structure comprising nine GaInNAs/GaNAs quantum wells with 15 periods of GaAs/AlAs distributed Bragg reflector (DBR) as bottom mirror. Photoluminescence (PL), electroluminescence (EL), and spectral photocurrent measurements confirm device operation within the telecom O-band, with emission and detection centred at 1280 nm and a narrow full-width at half-maximum (FWHM) of 65 nm. The NC capacitance is observed in both the forward and the reverse bias conditions. The NC effect observed under forward bias is attributed to radiative recombination, while under reverse bias it is driven by defect-related carrier trapping and impact ionization mechanisms. These results provide a detailed understanding of NC mechanisms in multi quantum well p-i-n junctions diode structures.