High performance bulk photovoltaics in narrow-bandgap centrosymmetric ultrathin films

Mai, Haoxin; Lü, Teng; Sun, Qingbo; Elliman, R. G.; Kremer, Felipe; Catchpole, Kylie; Li, Qian; Yi, Zhiguo; Frankcombe, Terry J.; Liu, Yun

doi:10.1039/c9mh01744e

Cited by 8 publications

(1 citation statement)

References 53 publications

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“…There is a large volume of studies concluding that photovoltaic response in vertical heterostructures is dominated by interface band bending [12,14,[26][27][28], and tuning the interface properties controls the overall photovoltaic response in some cases [29,30]. However, there also exists a number of reports on the BPVE in vertical heterostructures comprising BiFeO 3 [31], BaTiO 3 [32,33], and BiVO 4 [34], where contributions from interfaces or the tensorial nature of the BPVE are not thoroughly examined. Therefore, clarifying the dominating photovoltaic mechanism in vertical ferroelectric heterostructures is of crucial importance for both fundamental studies and practical applications.…”

Section: Introductionmentioning

confidence: 99%

Crossover between Bulk and Interface Photovoltaic Mechanisms in a Ferroelectric Vertical Heterostructure

et al. 2022

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The bulk photovoltaic (BPVE) effect in crystals lacking inversion symmetry offers great potential for optoelectronic applications due to its unique properties, such as above-band-gap photovoltage and switchable photocurrent. Because of their large spontaneous polarizations, ferroelectric materials are ideal platforms for studying the BPVE. However, identifying the origin of an experimentally observed photovoltaic response is often challenging due to the entanglement between bulk and interface effects, leading to much debate in the field. This issue is particularly pronounced in vertical heterostructures, where the two effects are comparable. Here, we report crossover between bulk-and interface-dominant responses in vertical BiFeO 3 heterostructures when changing the photon energy. We show that well-above-bandgap excitation leads to a bulk photovoltaic response, but band-edge excitation requires interface band bending to separate the photocarriers. Our findings not only help to clarify contradicting reports in the literature, but also lay the foundation for a deeper understanding of the ferroelectric photovoltaic effect and its applications in various devices.

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