Piezo-phototronic Effect Enhanced Responsivity of Photon Sensor Based on Composition-Tunable Ternary CdS_xSe_1–x Nanowires

Abstract

The piezotronic effect and piezo-phototronic effect on materials and devices have been widely studied in binary semiconductors. Wide-band ternary semiconductors are a great class of materials with potential application in nano/microdevices, because of their continuously tunable physical properties with composition. Here, we first demonstrate the piezo-photronics effect of ternary wurtzite structured nanowires (NWs), opening an innovative materials system. Single-crystal ternary CdS x Se 1−x (x = 0.85, 0.60, and 0.38) NWs were synthesized with site-controlled compositions via a chemical vapor deposition process, and high-performance visible photodetectors (PDs) with fast response speed (<2 ms), high photosensitivity, high responsivity, and broadened photoresponse region (than CdS NW) were fabricated based on these ternary materials. By introducing an external tensile strain, the performance of PDs is enhanced by 76.7% upon 0.2 mW/cm 2 442 nm light illumination for CdS 0.85 Se 0.15 by the piezo-phototronic effect. The composition effect of materials in ternary materials on light detecting and piezo-phototronics was also first investigated systematically. The results indicate that in the CdS x Se 1−x system, as the value of x decreases, the photocurrent and responsivity experience an increase, while the enhancement of the piezo-phototronic effect was weakened. The change in piezoelectric coefficient and carrier screening effect are proposed for the observed phenomenon. This study reports a high-quality ternary CdS x Se 1−x NWs system used for high-performance PDs, broadens the family of piezotronic materials, offers an innovative material for high-performance visible PD, and provides a new pathway to modulate the performance of piezo-phototronic devices by tuning the atomic ratios of ternary wurtzite semiconducting materials. This is essential for developing a full understanding of piezotronics on a broader scope, and it also enables the development of the better performance of optoelectronic devices.

A Self‐Powered Brain‐Linked Vision Electronic‐Skin Based on Triboelectric‐Photodetecing Pixel‐Addressable Matrix for Visual‐Image Recognition and Behavior Intervention

“…It can be found that the variation of the current upon illumination increases as the applied light intensity increases. The photosensitivity S of the e‐skin can be simply defined asin which I d and I 1 represent the outputting triboelectric current in darkness and under illumination, respectively. As shown in Figure d,e against 20, 40, 60, 80, and 100 µW cm −2 illumination, the photosensitivity is 14.0, 19.8, 22.8, 30.2, and 34.3, respectively.…”

Piezoelectric Semiconducting Nanowires

“…The piezoelectric properties of III-As and III-P have not received significant attention, despite being known and utilized for electro-mechanical applications [121,122]. The main reasons for that are the lower piezoelectric coefficients, and non-polar technology ([001] and [110] cubic orientations in zinc-blende), prevailing non-nitride III-V bulk electronic and optoelectronic technology [123,5]. Nonetheless, the various nanostructures Vs. bulk distinctions described in Section 3, apply to non-nitride III-Vs as well.…”

“…A brief summary of different ZnO NW structure designs for piezoelectric nanogenerator fabrication to WZ/ZB mixed phase NWs. In a later work, the piezotronic effect was also demonstrated on CdS and CdSe NWs[109,110], and energy harvesting with CdTe NWs[111].…”

Piezo-mechanical impedance of nanosized CdS single crystal

“…The mechanical vibrations of the nanocrystal were recorded by an optical interferometric method, but current-voltage output was not measured. Piezo-phototronic effect enhanced responsivity and influence of piezo-effect on the junction properties of nanosized CdS x Se 1-x single crystal was investigated experimentally and explained theoretically for frequency scale much below piezoresonance [13].…”