High-responsivity hybrid α-Ag₂S/Si photodetector prepared by pulsed laser ablation in liquid

Abstract

We report the synthesis of α-Ag2S nanoparticles (NPs) by one-step laser ablation of a silver target in aqueous solution of thiourea (Tu, CH4N2S) mixed with cationic cetyltrimethylammonium bromide (CTAB) as surfactant. The effect of the CTAB surfactant on the structural, morphological, optical, and elemental composition of Ag2S NPs was evaluated using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and UV–vis spectroscopy. The optical absorption decreased and the optical energy gap of α-Ag2S increased from 1.5 to 2 eV after the CTAB surfactant was added to the Tu solution. XRD studies revealed that the synthesized Ag2S NPs were polycrystalline with a monoclinic structure and that crystallinity of the nanoparticles was improved after adding CTAB. Raman studies revealed the presence of peaks related to Ag–S bonds (Ag modes) and the longitudinal optical phonon 2LO mode. Scanning electron microscopy investigations confirmed the production of monodisperse Ag2S NPs when using the CTAB surfactant. The optoelectronic properties of α-Ag2S/p-Si photodetector, such as current–voltage characteristics and responsivity in the dark and under illumination, were also improved after using the CTAB surfactant. The responsivity of the photodetector increases from 0.64 to 1.85 A/W at 510 nm after adding CTAB. The energy band diagram of the α-Ag2S/p-Si photodetector under illumination was constructed. The fabricated photodetectors exhibited reasonable stability after three weeks of storage under ambient conditions with a responsivity of 70% of the initial value.

High responsivity of VIS-NIR photodetector based on Ag2S/P3HT heterojunction

“…The optical responsivity of the device is lager under the 532 nm laser irradiation than under 405 and 808 nm, it indicates that Ag 2 S QDs with P3HT have stronger response to visible light. Compared with the already reported Ag 2 S QDs PD and single polymer PD, the responsivity has been greatly improved [31,32]. Another parameter that characterizes the detecting ability of a device is the specific detectivity D * , defined as follows [33,34]:…”

A new sensing platform based on a ternary nanocomposite of graphitic carbon nitride–silver sulfide–nickel molybdate for quercetin determination

“…The peaks at 1460 and 1650 cm −1 belong to the C–C and sulfide group stretching vibrations, respectively. 45 Besides, the broad and small peaks at approximately 3300 and 1660 cm −1 can be attributed to the stretching and bending vibrations of the O–H bond arising from the H 2 O molecules adsorbed on the Ag 2 S surface. 46 Similarly, the stretching and bending vibrations of the O–H bond were obtained in the FT-IR spectrum of the NiMoO 4 nanoparticles at wavenumbers of approximately 3400 and 1622 cm −1 .…”

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

“…( 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 . …”