The piezo‐phototronic effect is confirmed as a promising methodology to optimize the performance of optoelectronic devices. However, not only positive effects, but also negative effects may be produced in some types of photodiodes (PDs) by the piezo‐phototronic effect, resulting in the restriction of the PDs' photoresponse performance enhancement. In order to obtain the largest possible photoresponse performance enhancement, it is essential to investigate how the piezo‐phototronic effect influences the photoresponse performance of PDs with different device configurations and structures. Here, the piezo‐phototronic effect on the photoresponse performance enhancement of anisotype (p‐Si/n‐ZnO) and isotype (n‐Si/n‐ZnO) heterojunction PDs is thoroughly investigated. The experimental results show that the piezo‐phototronic effect induced improvement of the p‐Si/n‐ZnO heterojunction PD is much larger than that of the n‐Si/n‐ZnO heterojunction PD. The energy band diagrams under compressive strains are carefully analyzed, revealing that two positive effects are introduced to the p‐Si/n‐ZnO heterojunction PD, whereas one positive and two negative effects are introduced to the n‐Si/n‐ZnO heterojunction PD by the piezo‐phototronic effect. This work presents an in‐depth understanding about the piezo‐phototronic effect on the photoresponse performances of PDs with different device configurations and structures.

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The piezo‐phototronic effect has been extensively investigated to improve the performance of optoelectronic devices. However, the modulations in different energy band structures are quite distinctive, and adverse effects may be produced. Therefore, it is essential to investigate the modulation law in the optoelectronic devices with different energy band structures. Here, five kinds of Si/ZnO heterojunction photodiodes (PDs) with different energy band structures are fabricated and the piezo‐phototronic effect is systematically investigated on their photoresponse performance. For the p‐Si/n‐ZnO PDs, significant performance improvement is achieved by the piezo‐phototronic effect, with the magnitude of improvement increasing with doping concentration of p‐Si. For the n‐Si/n‐ZnO PDs, performance improvement is only achieved when the n‐Si is lightly doped, with a lower magnitude compared to that of the p‐Si/n‐ZnO PDs. The in‐depth working mechanism regarding to the different energy band structures is revealed. It is concluded that when the Fermi‐level of Si moves from the bottom of conduction band to the top of the valence band, the magnitude of performance improvement in Si/ZnO heterojunction PD increases. This study not only presents an in‐depth understanding regarding the piezo‐phototronic effect in Si/ZnO heterojunction PDs, but also provides guidance to optimize the piezo‐phototronic effect in optoelectronic devices.

The pulse radiation detectors are sorely needed in the fields of nuclear reaction monitoring, material analysis, astronomy study, spacecraft navigation, and space communication. In this work, we demonstrate a nanosecond X-ray detector based on ZnO single crystal semiconductor, which emerges as a promising compound-semiconductor radiation detection material for its high radiation tolerance and advanced large-size bulk crystal growth technique. The resistivity of the ZnO single crystal is as high as 1013 Ω cm due to the compensation of the donor defects (VO) and acceptor defects (VZn and Oi) after high temperature annealing in oxygen. The photoconductive X-ray detector was fabricated using the high resistivity ZnO single crystal. The rise time and fall time of the detector to a 10 ps pulse electron beam are 0.8 ns and 3.3 ns, respectively, indicating great potential for ultrafast X-ray detection applications.