Broadband and High‐Sensitivity Photodetector Based on BiFeO₃/Si Heterojunction

Abstract

Photovoltaic devices based on ferroelectric materials have broad application prospects; however, there are also problems of narrow bandwidth and low sensitivity. In this paper, polycrystalline BiFeO3 (BFO) films are prepared directly on n‐Si (100) substrates to form ferroelectric/semiconductor heterostructures, the electrical response of which under weak light intensity (0.8 W m−2) is systematically investigated. Accompanied by the dielectric relaxation originated from photocarriers, the polarization of BFO increases while the coercive voltage decreases. Especially, current–voltage (I–V) curve under negative bias voltage changes obviously with illumination, and cyclically switchable photocurrent is detected at 0 V bias, with the on‐off ratio increasing for lower temperature. Although the photoresponse is detectable in the broad wavelength range of 275–1100 nm, it is more pronounced for visible light. It is considered that the built‐in electric field of the PN junction at the BFO/n‐Si interface drives the separation and migration of photocarriers, which in turn affects the interface barrier and the distribution of monovalent oxygen vacancies (VO•$V_{\rm{O}}^ \bullet $) in BFO while producing the photovoltaic effect. This work provides an effective route for developing photodetectors with high sensitivity and broadband detection.

Ultra-Broadband High-Entropy Oxide Absorber Layer for Enhanced Photodetector Performance

“…The EQEs at different wavelengths of 580, 850, 940, and 1000 nm are 353, 732, 223, and 242%, respectively. These values are much better than those of the other reported oxide-based PDs and comparable to those of the polymer-based or polymer-containing PDs. − ,,,− The remarkable EQE values obtained under broadband illumination indicate the involvement of a trap-assisted photomultiplication effect that boosts the EQE. − …”

“…The PD was shown to be sensible from the deep UV (200 nm) to mid-wave IR (4.6 μm) and deliver an R value of 634.5 mA/W and a D * value of 4.3 × 10 11 Jones. Lei et al reported a BiFeO 3 /n-Si device, showing a broadband photoresponse from 275 to 1100 nm ( R = 0.97 mA/W and D = 7.8 × 10 11 Jones at 650 nm) . Li et al fabricated a MAPbI 3 /F8IC:PTB7-Th broadband (300–1000 nm) PD, showing R values of 0.37 A/W at 870 nm and 0.43 A/W in the visible range, an EQE over 63% from 380 to 780 nm, and a D * of 2.3 × 10 11 Jones at 870 nm .…”

“…Lei et al reported a BiFeO 3 /n-Si device, showing a broadband photoresponse from 275 to 1100 nm (R = 0.97 mA/ W and D = 7.8 × 10 11 Jones at 650 nm). 12 Li et al fabricated a MAPbI 3 /F8IC:PTB7-Th broadband (300−1000 nm) PD, showing R values of 0.37 A/W at 870 nm and 0.43 A/W in the visible range, an EQE over 63% from 380 to 780 nm, and a D* of 2.3 × 10 11 Jones at 870 nm. 13 Zhu et al reported a ternary perovskite-organic broadband (375−1000 nm) PD based on MAPbI3, 4-fluorobenzylammonium, and O6T-4F, showing an ultrahigh D* of 1.06 × 10 15 Jones, an R value of 0.36 A/W, and an EQE of 92% at 500 nm.…”

Inverted‐Structural Self‐Powered Gan/PZT/ITO UV Photodetector Enhanced by Ferroelectric Modulation

“…[35,36] Based on the modulation and coupling effects, several studies have reported performance enhancements in self-powered UV photodetectors by utilizing ferroelectric materials. [37][38][39][40][41][42] However, the performances of these devices are still relatively low, which restricts their applications. One of the main reasons is that the ferroelectric polarization of the ferroelectric film is not strong enough to remarkably enhance the built-in electric field.…”

Robust and Tunable Ferroelectricity in Ba/Co Codoped (K0.5Na0.5)NbO3 Ceramics

“…As we know, oxygen vacancies could pin the polarization switching, the reduction of the oxygen vacancies would lead to an easier polarization switching. [22,27] Since there are more oxygen vacancies in the SC sample, in order to clearly understand the impacts of oxygen vacancies, we conducted oxygenation treatment on the SC sample, which was to raise the temperature to 440 ∘ C in oxygen atmosphere and maintain for 30 min. The hysteresis loops and the corresponding parameter changes of the SC-O2 sample are shown in Figs.…”