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Photodetectors based on n‐Mg0.25Zn0.75O/p‐Si heterojunctions are not only suitable for integration with existing semiconductor technology, but also circumvent the difficulty of stable p‐type doping in MgxZn1–xO. However, the use of Si leads to photoresponse in the visible part of the light spectrum, which renders n‐MgxZn1–xO/p‐Si heterojunction devices unsuitable for visible blind UV photodetection. Herein, it is demonstrated that the visible photoresponse in the n‐Mg0.25Zn0.75O/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‐Mg0.25Zn0.75O, 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‐Mg0.25Zn0.75O/p‐Si heterojunction devices with MgO interlayer are promising for visible‐blind UV photodetection applications. [ABSTRACT FROM AUTHOR]

Herein, diode characteristics of n‐MgxZn1−xO/p‐Si heterojunctions grown by pulsed laser deposition at different oxygen ambient pressures are investigated. It is found that the heterojunctions grown at lower oxygen growth pressure of 1.0 × 10−2 mbar and below do not show rectifying diode‐like behavior, whereas those grown at higher oxygen pressures at and above 2.5 × 10−2 mbar exhibit perfect diode‐like rectifying characteristics. The diode characteristics are found to improve significantly with increasing oxygen ambient pressure during the growth of MgxZn1−xO film. The current–voltage measurements show that the n‐MgxZn1−xO/p‐Si heterojunction diode grown at a higher oxygen ambient pressure of ≈1.0 × 10−1 mbar has the lowest reverse saturation current of ≈19 nA and highest rectification ratio of ≈1.4 × 104. The capacitance–voltage measurements reveal that the depletion layer width of heterojunction diodes increases manifold with increasing oxygen ambient pressure during the growth of MgxZn1−xO, which is understood in terms of decrease in carrier concentrations in the MgxZn1−xO thin films grown at higher oxygen ambient pressures. The n‐MgxZn1−xO/p‐Si heterojunction diodes, grown at high oxygen ambient pressures, with low reverse saturation current, high rectification ratio, and large depletion width may have potential application in wide‐bandgap nanoelectronic devices and UV enhanced photodetectors. [ABSTRACT FROM AUTHOR]

Herein, it is shown that the UV photoresponse characteristics of MgZnO thin films deposited by pulsed laser deposition change rapidly with time if the films are exposed to ambient air and that the response can be stabilized significantly by depositing a thin capping layer of MgO on the surface of MgZnO thin film. The decay time of photocurrent in as‐deposited MgZnO thin films increases from 1.8 to 229 s and the value of peak responsivity increases by about three orders of magnitude as the film is exposed to air for about 106 s. On application of MgO capping layer, the decay time of the photocurrent marginally increases from ≈0.2 to ≈0.4 s and the value of peak responsivity increases only by one order of magnitude over the span of 106 s, thereafter showing tendency of saturation, implying much better stability in performance. The MgO capping layer is transparent to UV, but acts as a diffusion barrier for oxygen, stabilizing the UV photoresponse. [ABSTRACT FROM AUTHOR]