The effect of electrode shape on Schottky barrier and electric field distribution of flexible ZnO photodiode

Zahra Aminrayai Jezeh,Babak Efafi,Bijan Ghafary

doi:10.1038/s41598-021-95203-3

Zahra Aminrayai Jezeh, Babak Efafi + Show 1 more

Open Access

https://doi.org/10.1038/s41598-021-95203-3

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Abstract

In this study, the effect of electrode shape difference on the height of the Schottky barrier and the electric field in flexible photodiodes (PDs) has been investigated. For this purpose, three different electrode designs were prepared on three flexible FR4 layers that were coated with Zinc Oxide (ZnO). The printing circuit board (PCB) method was used to create these copper electrodes. The asymmetry of the PD electrodes and the difference in the height of the Schottky barrier has led to the creation of self-powered PDs. The effect of the amount and shape of the distribution of internal electric fields generated in the PDs and its effect on the parameters of the PDs has been investigated with the help of simulations performed in COMSOL software. The photocurrent of the sample with circular and rectangular electrodes was equal to 470 µA in 15 V bias, which was twice as good as a sample with an interdigitated MSM structure. Also, this sample had the best response time among these three samples, which was equal to 440 ms.

Highlights

In recent years, the field of flexible and wearable electronic components such as smartwatches, smart glasses and wearable cameras has been growing rapidly
Given that many other research groups have worked to improve the parameters of PDs, and for this purpose have used difficult and costly methods that have the possibility of error, so we were looking for another factor that is effective, easy, and inexpensive that was the effect of electrode shape on Schottky barrier and electric field distribution of PDs
The effect of electrode shape on the parameters of flexible UV PDs based on porous Zinc Oxide (ZnO) on the fiberglass (Fr4) substrate was investigated

Summary

Results and discussion

ZnO thin films’ phase pattern is determined using XRD at room temperature with a PANalytical PW3050/60 diffractometer using Cu Ka radiation at 40 kV and 40 mA. Oxygen molecules absorb ZnO nanomaterials’ surface and deplete electrons, creating a thin depletion layer with low electrical conductivity. The holes move to the ZnO surface due to the bending band and discharge of the adsorbed oxygen molecules, leading to the aggregation of electron concentrations and increasing the electrical conductivity. The effect of oxygen is that it captures free electrons in dark conditions and trap holes in illumination, increasing the life cycle of photogenerated carriers and improving the photoelectric response performance of ZnO porous films[30].

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Conclusion

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