Blocking Si‐Induced Visible Photoresponse in n‐MgxZn1–xO/p‐Si Heterojunction UV Photodetectors Using MgO Barrier Layer. Issue 22 (23rd September 2022)

• Record Type: Journal Article
• Authors: Chetia, Shantanu K.; Das, Amit K.; Ajimsha, Rohini S.; Banik, Soma; Singh, Rashmi; Padhi, Partha S.; Sharma, Tarun K.; Misra, Pankaj
• Is Part Of: Physica status solidi. Volume 219:Issue 22(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-09-23
• Subjects: heterojunctions -- MgO barrier layers -- MgxZn1–xO thin film -- pulsed laser deposition -- visible-blind UV photodetectors; Solid state physics -- Periodicals; Solids -- Industrial applications -- Periodicals; 530.41
• DOI: 10.1002/pssa.202200285
• Languages: English
• ISSNs: 1862-6300

Abstract

Abstract : Photodetectors based on n ‐Mg0.25 Zn0.75 O/p‐Si heterojunctions are not only suitable for integration with existing semiconductor technology, but also circumvent the difficulty of stable p‐type doping in Mg x Zn1– x O. However, the use of Si leads to photoresponse in the visible part of the light spectrum, which renders n ‐Mg x Zn1– x O/p‐Si heterojunction devices unsuitable for visible blind UV photodetection. Herein, it is demonstrated that the visible photoresponse in the n ‐Mg0.25 Zn0.75 O/p‐Si photodetectors can be significantly suppressed by inserting a thin interlayer of MgO at the heterojunction. The MgO layer serves as a blocking layer for the drift of photo‐excited electrons from p‐Si to n ‐Mg0.25 Zn0.75 O, thereby limiting the visible photoresponse. It is found that on increasing the thickness of the MgO interlayer from 3 to 15 nm, the UV to visible rejection ratio increases from ≈25 to 200. This enhancement in the UV to visible rejection ratio demonstrates that n ‐Mg0.25 Zn0.75 O/p‐Si heterojunction devices with MgO interlayer are promising for visible‐blind UV photodetection applications. Abstract : The visible photoresponse in n ‐Mg0.25 Zn0.75 O/p‐Si heterojunction could be significantly reduced by inserting a MgO barrier layer between the p‐Si substrate and the Mg0.25 Zn0.75 O film. The visible light suppression is caused by the presence of a high conduction band offset at the p‐Si/MgO interface that works as a barrier for the drift of the visible excited electrons from the p‐Si to n ‐Mg0.25 Zn0.75 O.