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DOE OSTI · 1764155

Photoelectrochemically Self Improving Si/GaN Photocathode: Figure 2d Raw Data

Abstract

After 10 hrs of chronoamperometry (CA) photoconductive atomic force microscopy (PC-AFM) measurements were conducted on Si/GaN samples using a commercial AFM system (Bruker Dimension Icon). PeakForce TUNA mode was used to acquire the morphology and current simultaneously. A PtIr conductive probe with spring constant of 2.8 Nm-1 was used for the scanning. A white light source was used to illuminate the surface during the acquisition. Line scan extracting the topography and photocurrent from this 10 hour CA tested Si/GaN sample. The topography mapping is 2 × 2 µm2. No sample bias was applied and this photoconductive AFM measurement was performed under white light front illumination with an angle.

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BibTeXRIS

Zeng, Guosong, Pham, Tuan Anh, Vanka, Srinivas, Liu, Guiji, Song, Chengyu, Cooper, Jason K, Mi, Zetian, Ogitsu, Tadashi, Toma, Francesca. 2021-02-04. Photoelectrochemically Self Improving Si/GaN Photocathode: Figure 2d Raw Data. https://doi.org/10.17025/1764155

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Photoelectrochemically Self Improving Si/GaN Photocathode: Figure 1a Raw Data

10 hours chronoamperometry (CA) testing under 1 sun illumination and constant bias at -0.6 V vs RHE, the corresponding Faradaic efficiency reveals a self-improving nature of GaN, inset: CA testing on bare Si for 5 hours under 1 sun illumination and -0.6 V vs RHE, this bare Si photocathode rapidly drops down to < 0.05 mA/cm2 within an hour. Both CA testing performed in 0.5 M H2SO4 (pH=0.4).

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Photoelectrochemically Self Improving Si/GaN Photocathode: Figure 1c Raw Data

Intermittent chronoamperometry (CA) testing was performed on Si/GaN photocathode in hourly manner. The LSV scan at 0 hour, 1 hour CA, 2 hours CA, 3 hours CA, 4 hours CA, 6 hours CA, 8 hours CA and 10 hours CA were recorded to track the changes of the photoelectrochemica (PEC) performance of the photocathode. The scan range was set to be 0V vs open circuit voltage (Eoc) to -0.7V vs RHE. Test was performed under one sun illumination in 0.5M H2SO4 (pH=0.4).

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