Semi-transparent quaternary oxynitride photoanodes on GaN underlayers

Abstract

Conformal atomic layer deposition (ALD) technique is employed to make semi-transparent Ta3N5, providing the possibility to build semi-transparent oxy(nitride) heterojunction photoanodes on conductive substrate. A generalized approach was developed to...

Recent Developments in Visible‐Light‐Absorbing Semitransparent Photoanodes for Tandem Cells Driving Solar Water Splitting

“…Transparent oxynitrides, such as LaTiO 2 N and SrTaO 2 N on GaN/Al 2 O 3 , have been also reported by Ma et al in 2020. [ 82 ] The oxynitrides prepared by spin coating of precursors followed by nitridation had high transparency (60–70%). The photocurrent values generated by LaTiO 2 N and SrTaO 2 N on GaN/Al 2 O 3 at 1.23 V versus RHE under simulated sunlight were found to be 20 and 7 μA cm −2 , respectively.…”

“…The photocurrent values generated by LaTiO 2 N and SrTaO 2 N on GaN/Al 2 O 3 at 1.23 V versus RHE under simulated sunlight were found to be 20 and 7 μA cm −2 , respectively. [ 82 ] It is noteworthy that these photoanodes showed photoresponse at about 0.0 V versus RHE. Therefore, oxynitride films are expected to produce photocurrent with a more negative onset potential compared to Ta 3 N 5 , resulting in improvement of STH efficiency.…”

Fabrication of Semi-Transparent SrTaO2N Photoanodes with a GaN Underlayer Grown via Atomic Layer Deposition

“…The emerged dark current density contribution is a common phenomenon for a pristine metal-based oxynitride photoelectrode, which is linked with the photocorrosion and the recombination of photocharges. 21,51,60 Since a bare GaN/SiC substrate does not present noticeable photoresponse, it excludes the photocurrent contribution from the substrate in the SrTaO2N photoanodes. Nevertheless, the insertion of an thin GaN film between the photoanode material and the SiC substrate is critical to supplying the pronounced photoresponse (vide infra).…”

Fabrication of Semi-Transparent SrTaO2N Photoanodes with a GaN Underlayer Grown via Atomic Layer Deposition

“…Fabrication of this type of PEC device is desired due to its advantages in low photon and photovoltage losses, and flexibility for industrial manufacture. 21,22 In particular, high transparency and efficiency of the front photoanode are critical prerequisites for achieving satisfied STH efficiency. 22 The photoanode has to transmit sunlight with a wavelength longer than its absorption edge to the rear side for reutilization by the photocathode (Figure 1).…”

“…19 The occurrence of more cathodic photocurrent onsets is also generally observed in oxynitride-driven systems, which makes them being very attractive photoanode candidates for tandem PEC cell. 19,21,26 Nonetheless, the fabrication process of transparent oxynitride thin films is demanding in comparison to oxides. Transparent quaternary oxynitride films have been previously obtained by pulsed laser deposition (PLD), 27,28 reactive radio frequency (RF) magnetron sputtering, [29][30][31][32] and spin-coating in conjunction with post-ammolysis.…”