Fig. 2: PPC effect and synaptic behavior of the a-GaOx DUV sensor. | Nature Communications

Fig. 2: PPC effect and synaptic behavior of the a-GaOx DUV sensor.

From: In-sensor reservoir computing system for latent fingerprint recognition with deep ultraviolet photo-synapses and memristor array

Fig. 2

a KPFM results of the a-GaOx surface after injecting electrons (top panel) and holes (bottom panel) by negative/positive biasing. The inset in each image indicates the potential profile along the white dashed line. b XPS spectral fitting of the O1s peak of the a-GaOx film with different oxygen contents (S1, S2, and S3). c The normalized photoresponse I-t curves of the a-GaOx films with different oxygen contents (S1, S2, and S3). d The macroscopic PPC and volatile STM effects observed in Ga2O3 photoelectronic device under various DUV pulse widths (25 ms, 50 ms, and 100 ms). The response current ΔI is the difference between the maximum photocurrent and the initial dark current. e PPF behavior of the a-GaOx photo-synapse induced by the PPC effect. Taking ΔI1 as the response current of the first stimuli and ΔI2 of the second, the PPF index is calculated as the ratio of ΔI2 to ΔI1. f Dependence of PPF indexes varying with pulse intervals from 45 ms to 1000 ms, fitted by a double-exponential function. Each pulse interval contains 10 measurements. g Influence of oxygen-vacancy-related traps on the generation, recombination, and regeneration processes of photo-generated carriers in the a-GaOx photo-synapse.

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