Preparation of novel B4C nanostructure/Si photodetectors by laser ablation in liquid

Abstract

In this study, boron carbide (B4C) nanoparticles (NPs) are synthesized by pulsed laser ablation of boron in ethanol at a laser fluence of 6.36 J cm−2 pulse−1. The effect of numbers of laser pulses on the structural, optical, and electrical properties of B4C NPs was studied. X-ray diffraction (XRD) results revealed that all B4C nanoparticles synthesized were polycrystalline in nature with a rhombohedral structure. When the laser pulses increased from 500 to 1500, the optical band gap of B4C decreased from 2.45 to 2.38 eV. Fluorescence measurements showed the emission of two emission peaks. The Raman spectra of B4C nanoparticles exhibit six vibration modes centered at 270, 480, 533, 722, 820, and 1080 cm−1. Field emission scanning electron microscope (FESEM) images show the formation of spherical nanoparticles of an average size of 68, 75, and 84 nm for samples prepared at 500, 1000, and 1500 pulses, respectively. The dark I–V characteristics of B4C/Si heterojunction photodetectors showed rectification characteristics, and the heterojunction prepared at 500 pulses exhibits the best junction characteristics. The illuminated I–V characteristics of B4C/p-Si heterojunction photodetectors exhibited high photosensitivity to white light. The spectral responsivity of the p-B4C/p-Si photodetector shows that the maximum responsivity was 0.66 A W−1 at 500 nm for a photodetector prepared at 500 pulses. The highest specific detectivity and quantum efficiency were 2.18 × 1012 Jones and 1.64 × 102% at 550 nm, respectively, for a heterojunction photodetector fabricated at 500 pulses, The ON/OFF ratio, rise time, and fall time are measured as a function of the number of laser pulses. The photodetector fabricated at 1500 laser pulses showed roughly rise and fall intervals of 1.5 and 0.8 s, respectively.

Photovoltaic and mechanical properties of boron carbide films prepared by magnetron sputtering

“…The energy band diagram of a p-B 4 C/p-Si heterojunction photodetector was schematized in a previous study. 11) The p-B 4 C layer had a bandgap energy of 2.45 eV, and the p-B 4 C/p-Si heterojunction had a straddling bandgap (Type I). The conduction band offset (ΔE c = χ Si-χ B4C ) was 1.4 eV, and the valence band offset [ΔE v = (E gB4C -E gSi )-ΔE c ] was −0.07 eV, where χ is the electron affinity.…”

“…The photogenerated holes drifted from the Si side to the B 4 C side because ΔE v was small, which increased the photocurrent of the photodetector. 11) To appropriately consider the operation mechanism of the B x C (:H)/n-Si heterojunctions, their band alignments must be understood in the future.…”

“…9,10) B 4 C is a p-type semiconductor and is used in optoelectronic devices such as photodetectors, junction solar cells, and dye-sensitized solar cells. [11][12][13] The advantages of using B x C films in optoelectronic devices such as solar cells are as follows. (1) The bandgap energy (E g ) of B x C varies with its chemical composition.…”

Effect of laser fluence on the optoelectronic properties of nanostructured GaN/porous silicon prepared by pulsed laser deposition

“…Both Eqs. ( 5 ) and ( 6 ) 102 – 105 represent detectivity (D*) and external quantum efficiency (EQE), respectively I ph is the photocurrent (Ampere), and P is the incident power (Watt) 106 , 107 . where A is the area of photodetector, is the dark current of photodetector, and q is the electron charge 108 – 111 .…”

A novel method for ZnO@NiO core–shell nanoparticle synthesis using pulse laser ablation in liquid and plasma jet techniques

“… 8 , 25 , 26 . Recently, a hybrid method has been used that includes the pulse laser ablation in liquid (PLAL) and the plasma jet technique because of their many advantages, including cost-effectiveness, environmental friendliness, and a lack of need for expensive equipment 27 , 28 . Also, they don’t need a loge time in preparation just a few mints.…”