https://espace.library.uq.edu.au/view/UQ:e38288a/UQe38288a_OA.pdf

High-performance SnSe thermoelectric materials: Progress and future challenge

Atomically smooth, single crystalline Bi2Se3 thin films were prepared on Si(111) by molecular beam epitaxy. Scanning tunneling microscopy, low-energy electron diffraction, x-ray photoelectron emission spectroscopy, and Raman spectroscopy were used to characterize the stoichiometry and crystallinity of the film. The films grow in a self-organized quintuple layer by quintuple-layer mode, and atomically smooth films can be obtained, with controllable thickness down to one quintuple layer (∼1 nm).

Quintuple-layer epitaxy of thin films of topological insulator Bi2Se3

Apart from conventional materials, the study of two-dimensional (2D) materials has emerged as a significant field of study for a variety of applications Graphene-like 2D materials are important elements of potential optoelectronics applications due to their exceptional electronic and optical properties The processing of these materials towards the realization of devices has been one of the main motivations for the recent development of photonics and optoelectronics The recent progress in photonic devices based on graphene-like 2D materials, especially topological insulators (TIs) and transition metal dichalcogenides (TMDs) with the methodology level discussions from the viewpoint of state-of-the-art designs in device geometry and materials are detailed in this review We have started the article with an overview of the electronic properties and continued by highlighting their linear and nonlinear optical properties The production of TIs and TMDs by different methods is detailed The following main applications focused towards device fabrication are elaborated: (1) photodetectors, (2) photovoltaic devices, (3) light-emitting devices, (4) flexible devices and (5) laser applications The possibility of employing these 2D materials in different fields is also suggested based on their properties in the prospective part This review will not only greatly complement the detailed knowledge of the device physics of these materials, but also provide contemporary perception for the researchers who wish to consider these materials for various applications by following the path of graphene

https://iopscience.iop.org/article/10.1088/0957-4484/27/46/462001/pdf

Photonics and optoelectronics of two-dimensional materials beyond graphene.

Nanoelectronics is in urgent demand of exceptional device architecture with ultrathin thickness below 10 nm and dangling-bond-free surface to break through current physical bottleneck and achieve new record of integration level. The advance in 2D van der Waals materials endows scientists with new accessibility. This study reports an all-layered 2D Bi2Te3-SnSe-Bi2Te3 photodetector, and the broadband photoresponse of the device from ultraviolet (370 nm) to near-infrared (808 nm) is demonstrated. In addition, the optimized responsivity reaches 5.5 A W−1, with the corresponding eternal quantum efficiency of 1833% and detectivity of 6 × 1010 cm Hz1/2 W−1. These figures-of-merits are among the best values of the reported all-layered 2D photodetectors, which are several orders of magnitude higher than those of the previous SnSe photodetectors. The superior device performance is attributed to the synergy of highly conductive surface state of Bi2Te3 topological insulator, perfect band alignment between Bi2Te3 and SnSe as well as small interface potential fluctuation. Meanwhile, the all-layered 2D device is further constructed onto flexible mica substrate and its photoresponse is maintained roughly unchanged upon 60 bending cycles. The findings represent a fundamental scenario for advancement of the next generation high performance and high integration level flexible optoelectronics.

All-Layered 2D Optoelectronics: A High-Performance UV–vis–NIR Broadband SnSe Photodetector with Bi2Te3 Topological Insulator Electrodes

The indirect bandgap semiconductor tin selenide (SnSe) has been a research hotspot in the thermoelectric fields since a ZT (figure of merit) value of 2.6 at 923 K in SnSe single crystals along the b-axis is reported. SnSe has also been extensively studied in the photovoltaic (PV) application for its extraordinary advantages including excellent optoelectronic properties, absence of toxicity, cheap raw materials, and relative abundance. Moreover, the thermoelectric and optoelectronic properties of SnSe can be regulated by the structural transformation and appropriate doping. Here, the studies in SnSe research, from its evolution to till now, are reviewed. The growth, characterization, and recent developments in SnSe research are discussed. The most popular growth techniques that have been used to prepare SnSe materials are discussed in detail with their recent progress. Important phenomena in the growth of SnSe as well as the problems remaining for future study are discussed. The applications of SnSe in the PV fields, Li-ion batteries, and other emerging fields are also discussed.

https://www.onlinelibrary.wiley.com/doi/pdf/10.1002/advs.201700602

Tin Selenide (SnSe): Growth, Properties, and Applications.

Polycrystalline thin films of tin selenide have been prepared by reactive evaporation at substrate temperatures ranging from 473–600 K. Crystallites of the films prepared at substrate temperatures below 525 K are randomly oriented, while they have a strong preferred orientation on the substrate surface at higher substrate temperatures. Optical absorption studies indicate that the fundamental absorption starts at 1.21 eV and it is due to an allowed direct transition.

Tin selenide (SnSe) thin films prepared by reactive evaporation

Structural, electrical and optical properties of Bi2Se3 and Bi2Se(3−x)Tex thin films

Electrical properties of bismuth selenide (Bi2Se3) thin films prepared by reactive evaporation

Growth, morphology, and microindentation analysis of Bi2Se3, Bi1.8In0.2Se3, and Bi2Se2.8Te0.2 single crystals

An open cell configuration has been employed for the photoacoustic measurement of the thermal diffusivity of undoped Bi2Se3 crystals and Bi2Se3 crystals doped with various concentrations of Te. The amplitude of the photoacoustic signal obtained under heat transmission configuration as a function of chopping frequency is used to evaluate the numerical value of thermal diffusivity, α. Doped samples show a substantial reduction in the value of α compared to undoped samples. The variations in the thermal diffusivity of the doped samples are explained in terms of the phonon assisted heat transfer mechanism. It is seen that α is very sensitive to structural variations arising from doping. The experimentally observed results are correlated with X-ray diffraction studies.

/pdf/effect-of-te-doping-on-thermal-diffusivity-of-bi2se3-19sv9saqiy.pdf

Elizabeth Mathai

Papers

Tin selenide (SnSe) thin films prepared by reactive evaporation

Structural, electrical and optical properties of Bi2Se3 and Bi2Se(3−x)Tex thin films

Electrical properties of bismuth selenide (Bi2Se3) thin films prepared by reactive evaporation

Growth, morphology, and microindentation analysis of Bi2Se3, Bi1.8In0.2Se3, and Bi2Se2.8Te0.2 single crystals

Effect of Te doping on thermal diffusivity of Bi2Se3 crystals: A study using open cell photoacoustic technique