Development and characterization of photodiode from p-Cu₂CdSnS₄/n-Bi₂S₃ heterojunction

Here we investigated the photo response behaviour of p-Cu₂CdSnS₄ (p-CCTS)/n-Bi₂S₃ heterojunction photodiode. The solution processed CCTS films without any high temperature sulfurization demonstrated the photo response behaviour, suggesting the material is well suited for low temperature processed photovoltaic applications. A CCTS film was deposited on an ITO coated glass substrate using simple sol-gel based spin coating method. Current–voltage (I–V) characteristic of the p-CCTS/n-Bi₂S₃ heterojunction photodiode showed a good rectifying behaviour indicating better junction formation between CCTS and Bi₂S₃ layers. The obtained photocurrent is 4 times higher than that of the dark current. The I–V curves are asymmetric with respect to voltages and the photocurrent in the positive bias region is considerably higher than the corresponding values in the negative bias region. With these results, it is concluded that the CdS material in traditional thin film PV devices can be replaced with Bi₂S₃ for better transportation of charge carriers in the PN-junction. (paper)