With large surface-to-volume ratios and Debye length comparable to their small sizes, one-dimensional inorganic nanostructures have extensively been investigated and widely used to fabricate high-performance nanoscale electronic and optoelectronic devices This feature article reviews the state-of-the-art research activities that focus on the one-dimensional inorganic nanostructures and their photodetector applications It begins with a survey of one-dimensional inorganic nanostructures and the fundamentals of photodetectors Some remarkable photoresponse characteristics are then presented, which are organized into sections covering several kinds of important nanostructures, such as ZnO, V 2 O 5 , ZnS, In 2 Se 3 , InSe, CdS, CdSe, ZnSe, Sb 2 Se 3 , ZrS 2 , Ag 2 S, and Zn x Cd 1-x Se Each section describes the corresponding photodetective properties in detail Finally, the article concludes with some perspectives and outlook on the future developments in the field

Recent Developments in One-Dimensional Inorganic Nanostructures for Photodetectors

https://iopscience.iop.org/article/10.1088/2043-6254/aa853a/pdf

Impact of grain size and structural changes on magnetic, dielectric, electrical, impedance and modulus spectroscopic characteristics of CoFe2O4 nanoparticles synthesized by honey mediated sol-gel combustion method

Lanthanide-doped vanadate thin films offer (i) a promising platform for luminescence-based noncontact temperature sensing; (ii) ratiometric/self-referencing absolute measurements; (iii) exceptional repeatability and reversibility for multirun uses and a long life cycle; (iv) 2% K(-1) maximum temperature sensitivity (among the highest recorded for inorganic nanothermometers); (v) a temperature resolution greater than 0.5 K; and (vi) the potential for high-resolution 2D temperature mapping.

Pulsed Laser Deposited Dysprosium-Doped Gadolinium-Vanadate Thin Films for Noncontact, Self-Referencing Luminescence Thermometry.

The red shift and the broadening of the Raman signal from microcrystalline silicon films is described in terms of a relaxation in the q-vector selection rule for the excitation of the Raman active optical phonons. The relationship between width and shift calculated from the known dispersion relation in c-Si is in good agreement with available data. An increase in the decay rate of the optical phonons predicted on the basis of the same model is confirmed experimentally.

The one phonon raman spectrum in microcrystalline silicon

Different sizes of CdS nanobelts were synthesized at 800, 850, and 900 °C by the thermal evaporation of CdS powders on Au-coated silicon substrates and were used to study the size effects of Raman scattering and photoluminescent spectra. The Raman spectra of CdS nanobelts clearly exhibit first- and second-order longitudinal optical (LO) Raman peaks, surface phonon peaks, and multiphonon processes when excited using a wavelength of 532 nm. The mechanism of exciton–phonon coupling was observed to be mainly associated with the Frohlich interaction, and the coupling strength of the exciton–phonon increases with increasing lateral size. Compared with a larger CdS nanobelt, a narrower nanobelt exhibits a larger tensile strain. Recombination of free excitons (FX), excitons bound to neutral impurities (A0X), and donor–acceptor pairs (DAP) were identified from a low-temperature PL spectrum. At temperatures below ∼123 K, a red shift of the FX energy occurs with decreasing lateral size due to a larger uniaxial tensi...

Size Effects of Raman and Photoluminescence Spectra of CdS Nanobelts

Semiconductor photocatalyst nanomaterials are being extensively studied for last a few decades due to their great potentials in solving energy and environmental problems on the earth by harnessing solar light....

CdS based 3D Nano/Micro-Architectures: Formation Mechanism, Tailoring of Visible Light Activities and Emerging Applications in Photocatalytic H2 Production, CO2 Reduction and Organic Pollutant Degradation

Solution processed lead selenide (PbSe) colloidal quantum dots (CQDs) are indomitable for near infrared (NIR) and infrared optoelectronics. This is due to their low band gap and peculiar electronic structure that enables ultra-efficient multiple exciton generation for single photon absorption and size-tunable inter-band as well as intraband transitions observed experimentally. This chapter is all about efficient PbSe CQDs starting from brief introduction of the material followed by various synthesis methods adopted in due course of time. Surface treatments and ligand exchange are two important pillars of synthesis process to facilitate CQDs’ emission, electrical and electronic properties, so these will be discussed as subsections. The characterization and properties of as-synthesized CQDs will be taken up first and subsequently the factors affecting these properties which will on one hand aware us with the challenges and on the other hand enrich us with the solutions. The later section describes the fortitude of PbSe CQDs in various NIR optoelectronic devices right from device fabrication to its performance followed by challenges and the future scope of the field. 

Efficient PbSe colloidal QDs for optoelectronics devices

A report on the manipulation of structural, optical, and electrical properties of nanocrystalline CdS (ncCdS) thin films in the framework of varying Ar ambient pressure in pulsed laser deposition (PLD) is presented here. Increase in Ar ambient pressure results in reduction of crystallite size which in turns increases the structural imperfections and structural phase transformation of ncCdS thin films. The most significant observation here is the bleaching of multiphonon Raman modes (MRMs) particularly LO + 2E2, 2LO + 2E2, etc. in ncCdS thin films. An acute investigation on the reason of bleaching of LO + 2E2, 2LO + 2E2, etc. modes is carried out here and concluded that it is due to the fading of E2 mode with increasing Ar pressure as confirmed by low-frequency micro-Raman measurements. UV–visible absorption and photoluminescence spectroscopies are used to examine the optical properties like bandgap and possible electronic transitions in ncCdS thin films. Further, transport properties of ncCdS thin films are investigated using Hall measurement and I–V characteristics.

Vital role of Ar ambient pressure in controlled properties of nanocrystalline CdS thin films

Synthesis and modification of CdS:SiO 2 and Cd 0.99 Ag 0.01 S:SiO 2 nanocomposite thin films grown at substrate temperature 200 °C by pulsed laser deposition (PLD) followed by swift heavy ion irradiation (SHII) using 120 MeV Ag 9 + ions is reported. The structural evolution of CdS phase in SiO 2 after SHII is illustrated by glancing angle x-ray diffraction patterns and micro-Raman spectra. Transmission electron microscopy (TEM) images clearly show the growth of CdS/Cd 0.99 Ag 0.01 S nanoparticles in SiO 2 matrix under the influence of SHII. Photoluminescence (PL) spectra show two emission peak at ~ 2.34 eV and ~ 3.05 eV assigned for green emission (GE) and violet emission (VE) respectively. The VE assumed to be originated due to the band edge emission and GE identified as the trap levels located between conduction band and valence band. The presence of emission from pristine films indicates that the crystalline domains are very small in films rather than the particles are amorphous in nature. A systematic increment in PL emission intensity corresponding to trap emission as a function of ion irradiation fluence is observed from the two nanocomposite systems. However, the behavior of band edge emission induced by SHII is quite different in two nanocomposite systems. SHII induced phase formation and emission intensity variation as a function of ion fluence are explained on the basis of thermal spike model.

Swift heavy ion induced structural phase generation and enhanced luminescence from CdS based nanocomposites

Intense red emission is achieved in silicon nanocrystals (SiNCs) grown by atom beam sputtering (ABS) followed by ion beam irradiation (IBI). The silicon rich silicon oxide thin films are grown by ABS technique with target consisting of 60% silicon-in-excess + SiO2. To precipitate the excess silicon in the form of nanocrystals, samples were processed under IBI post deposition treatment. IBI of the films is carried out using a 160 MeV Ni+ 11 ion beam at fluences 5 × 1012, 1 × 1013 and 5 × 1013 ions/cm2. The transmission electron microscopy (TEM) studies reveal that the size of the nanocrystals increases monotonically as the ion fluence is increased. The IBI treated samples show almost monodispersion at all fluences and the size of the particles can be controlled precisely by ion fluence. The photoluminescence (PL) studies support the TEM results and an intense emission with a red shift is observed as the particle size is increased with an increase in ion fluence. The asymmetry in transverse optical (TO) vibrational mode in Raman spectra also suggests the formation of SiNCs in the SiO2 films.

Pragati Kumar

Papers

CdS based 3D Nano/Micro-Architectures: Formation Mechanism, Tailoring of Visible Light Activities and Emerging Applications in Photocatalytic H2 Production, CO2 Reduction and Organic Pollutant Degradation

Efficient PbSe colloidal QDs for optoelectronics devices

Vital role of Ar ambient pressure in controlled properties of nanocrystalline CdS thin films

Swift heavy ion induced structural phase generation and enhanced luminescence from CdS based nanocomposites

Formation of luminescent Si nanocrystals by ion irradiation