On the Piezo‐Phototronic Effect in Si/ZnO Heterojunction Photodiode: The Effect of the Fermi‐Level Difference

Abstract

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.

A new strategy: fermi level control to realize 3D pyramidal NiCo-LDH/ReS2/n-PSi as a high-performance photoanode for the oxygen evolution reaction

“…As we know, the band gaps of Si and ReS 2 are 1.12 eV and 1.51 eV, respectively. 23,31 And it is a typical Z-scheme band structure between Si and ReS 2 . Typically, holes came from the valence band (VB) of Si will recombine with electrons in the conduction band (CB) of ReS 2 to form a recombination center at the interface.…”

“…However, it can be predicted that a different silicon doping type may result in an unequal band alignment because of the Fermi level matching. 31,32 Up to now, using an n-type Si substrate or fabricating a TMD/Si photoanode in PEC water splitting for the OER has not been reported. 28 Such an absence limits the use of TMD/Si in a dual photoelectrode system (like photo-fuel cells) with the same surface material (like ReS 2 ) as both a photocathode and photoanode, because the same surface material can perfectly solve the energy barrier between the two photoelectrodes due to the difference in work function and affect the properties in PEC water splitting.…”

Light Emission Enhancement of a ZnO/TAZ Heterostructure Piezo‐OLED by Means of a Piezo‐Phototronic Effect

“…Each pixel containing a piezo-zinc oxide/TAZ OLED can respond to partial pressure, force, and strain thanks to the piezo-optical effect. [22][23][24][25] The electroluminescence signal of all pixels is read out in parallel with a temporal resolution of 100 ms to obtain the pressure output. The information collected from this array of self-luminous strain sensor, when paired with on-chip optical communication technology, allows for rapid optical communication and processing, so as to develop an extremely intelligent man-machine interface.…”

Enhanced luminescence/photodetecting bifunctional devices based on ZnO:Ga microwire/p-Si heterojunction by incorporating Ag nanowires

“…Si-based materials and devices are one of basic building blocks of semiconductor electronics technology in the last half century, and have attracted extensive attentions on solar cells, light-emitting sources, photodiodes and so on. [1][2][3][4][5][6][7] Due to the low-cost, highabundance and desired electrical properties, Si-based structures are crucial issue to meet the needs of modern communication, processors, integrated circuits, etc. [8][9][10] However, limited by the low carrier mobility, indirect band structure and the insulating layer around the surfaces, one of the crucial challenges in Sibased optoelectronic devices is developing power-efficient, highspeed, integrated, and smart optoelectronic devices.…”