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The piezophototronic effect has been widely explored to improve the performance of optoelectronic devices. However, modulation of piezoelectric charges varies with different energy band structures. Thus, it is important to investigate the specific role of the piezophototronic effect from a theoretical perspective. Herein, the piezophototronic effect in anisotype p‐Si/n‐ZnO heterojunction photodiodes with type‐II energy band diagrams through analytical derivation and numerical simulation is thoroughly studied. It is found that both the depletion region and quasineutral region have a decisive effect on photocurrent in their respective regions. Specifically, modulations of piezoelectric charges on depletion region current and quasineutral region current are opposite and compensate each other, resulting in reduced piezophototronic effect. Heterojunctions under short diode conditions are preferred for better piezophototronic effect as modulation on quasineutral region current is weakened while that on depletion region current remains unchanged. The effects of doping concentration, absorption coefficient, and minority carrier lifetime of semiconductor materials on device characteristics are also studied. This work provides deeper insight into the underlying device physics of the piezophototronic effect. [ABSTRACT FROM AUTHOR]

The piezo‐phototronic effect can modulate the dynamics of photo‐generated carriers by utilizing external‐strain–induced piezoelectric charges (piezo‐charges). Most of the current researches focus on the modulation effect on the optoelectronic properties of p–n junctions. There are only a few studies focusing on the metal‐oxide–semiconductor (MOS) structures. In this work, a PEDOT:PSS/Al2O3/n‐ZnO tri‐layer MOS tunneling junction is fabricated and the piezo‐phototronic effect on its photo‐carriers dynamic and performances is systematically investigated. The photoresponsivity to 365 nm laser illumination is reduced because of the negative piezo‐charges generated at the Al2O3/n‐ZnO interface. Meanwhile but unexpectedly, the similar phenomenon utilizing the positive piezo‐charges at the Al2O3/n‐ZnO interface is observed. The in‐depth working mechanisms are carefully investigated by analyzing the effect of piezo‐charges on the energy band diagram. Strain induced piezo‐charges could feasibly adjust the intermediate oxide layer's barrier height and width so that the tunneling effect can be efficiently modulated by the piezo‐phototronic effect, leading to the effective control over the MOS tunneling junction's photo‐carriers dynamic and corresponding photoresponses. This work provides an in‐depth understanding for the piezo‐phototronic effect on the MOS tunneling junction and provides guidance for the subsequent researches on the coupling of piezo‐phototronic effect and tunneling effect. [ABSTRACT FROM AUTHOR]

Accurate passive intermodulation (IM) test calls for precise IM reference for verifying and evaluating the test error from the tester, which makes the IM calibrator source with a wide working band and dynamic range important. This letter reports on a low‐cost and broadband IM generator with a compact area of 5 × 5 cm2. The broadband IM source is designed and demonstrated on the coplanar waveguide structure, where an artificial nonlinear dipole is used to generate IM reference. In special, the dipole is constructed by a diode (HSMS 2822) and two independent copper islands with optimized size. By controlling the bias voltage across the diode, the IM magnitude level can be changed accordingly. The IM tunable dynamic range is over 47.5 dB that covers GSM 800 MHz, GSM 900 MHz, DCS 1800 MHz, and TD‐LTE band. Meanwhile, the obtained IM has an improved IM‐bias flat response. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Abstract: 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. [ABSTRACT FROM AUTHOR]

An on‐line passive intermodulation test method for conductive coating is presented. A split‐type rectangular coaxial line is working as test fixture. As the standing wave of this test fixture can stay small in the replacement of coating samples, passive intermodulation test can always continue. By using this test method, several coatings are rapidly distinguished from their different passive intermodulation performance. A fast passive intermodulation test method for coatings is demonstrated. [ABSTRACT FROM AUTHOR]

The head-tail connector of bacteriophage ϕ29 is composed of 12 36 kDa subunits with 12-fold symmetry. It is the central component of a rotary motor that packages the genomic dsDNA into preformed proheads. This motor consists of the head-tail connector, surrounded by a ϕ29-encoded, 174-base, RNA and a viral ATPase protein, both of which have fivefold symmetry in three-dimensional cryo-electron microscopy reconstructions. DNA is translocated into the prohead through a 36 Å diameter pore in the center of the connector, where the DNA takes the role of a motor spindle. The helical nature of the DNA allows the rotational action of the connector to be transformed into a linear translation of the DNA. The crystal structure determination of connector crystals in space group C2 was initiated by molecular replacement, using an approximately 20 Å resolution model derived from cryo-electron microscopy. The model phases were extended to 3.5 Å resolution using 12-fold non-crystallographic symmetry averaging and solvent flattening. Although this electron density was not interpretable, the phases were adequate to locate the position of 24 mercury sites of a thimerosal heavy-atom derivative. The resultant 3.2 Å single isomorphous replacement phases were improved using density modification, producing an interpretable electron-density map. The crystallographically refined structure was used as a molecular-replacement model to solve the structures of two other crystal forms of the connector molecule. One of these was in the same space group and almost isomorphous, whereas the other was in space group P21212. The structural differences between the oligomeric connector molecules in the three crystal forms and between different monomers within each crystal show that the structure is relatively flexible, particularly in the protruding domain at the wide end of the connector. This domain probably acts as a bearing, allowing the connector to rotate within the pentagonal portal of the prohead during DNA packaging. [ABSTRACT FROM AUTHOR]

The head-tail connector of bacteriophage ϕ29, an oligomer of gene product 10 (gp10), was crystallized into various forms. The most useful of these were an orthorhombic P22121 form (unit-cell parameters a = 143.0, b = 157.0, c = 245.2 Å), a monoclinic C2 form (a = 160.7, b = 143.6, c = 221.0 Å, β = 97.8°) and another monoclinic C2 form (a = 177.0, b = 169.1, c = 185.2 Å, β = 114.1°). Frozen crystals diffracted to about 3.2 Å resolution. There is one connector per crystallographic asymmetric unit in each case. Rotation functions show the connector to be a dodecamer. Translation functions readily determined the position of the 12-fold axis in each unit cell. The structure is being determined by 12-fold electron-density averaging within each crystal and by averaging between the various crystal forms. [ABSTRACT FROM AUTHOR]

The piezo‐phototronic effect is widely used to regulate the interface of multilayer structures to tune the transportation of carriers by mechanical strain‐induced piezoelectric polarization charges. Besides, such modulation of the interface can also be achieved by the flexoelectric polarization charges induced by the mechanical strain gradients. Therefore, it is expected these two kinds of polarization charges can cooperate. In this work, a flexible phototransistor array based on n‐AZO/p‐Si/n‐ZnO structure is successfully demonstrated. The piezoelectric and flexoelectric polarization charges generated at the interfaces of the collector junction and the emitter junction, combined with the natural hole barrier at the emitter‐based interface, leads to the excellent performance of phototransistor for the ultraviolet (UV) –near infrared (NIR) range. Moreover, strain/optical imaging based on the flexible phototransistor array under different wavelengths of light is systematically investigated. The physical mechanism of the coupling between piezo‐phototronic and flexoelectric effects is further studied by analyzing the energy band and found to be attributed to the improvement of the emission efficiency and base transport efficiency. This work not only proposes a high‐performance flexible phototransistor array but also provides a new methodology to effectively modulate the interface by coupling the piezo‐phototronic effect and the flexoelectric effect. [ABSTRACT FROM AUTHOR]