Nanocomposite CdSe/Cr₂Se₃: Synthesis, Characterization, and in situ Transformation Study

Abstract

A 0‐3 nanocomposite of CdSe (crystalline nanoparticles) and Cr2Se3 (amorphous matrix) was synthesized via a soft chemical approach and characterized by X‐ray diffraction (XRD) and transmission electron microscopy (TEM). Particularly the transformation of the 0‐3 composite is explored in situ under electron beam irradiation and thermal annealing inside the TEM. In situ electron beam irradiation removed exclusively the CdSe nanoparticles and generated a porous Cr2Se3 matrix with a slightly increased crystallinity. The highly localized beam heating and knock‐on effect are attributed to the origin of the in situ irradiation transformation. During the in situ thermal annealing process of the 0‐3 nanocomposite CdSe particles are eliminated and crystalline nano‐ and microparticles of Cr2Se3 are generated. Also the formation of chromium enriched crystallites is observed. All of these in situ results are compared with conventional ex situ methods and discussed in terms of the different mechanisms associated with electron beam interaction and size effects of the nanocomposite.

Structural and magnetic properties of molecular beam epitaxy grown chromium selenide thin films

“…Bulk crystal growth of Cr2Se3 has been achieved previously by various methods, e.g., ceramic method [6][7][8][9], solid state reaction method [10][11][12][13]16], soft chemical and hydrothermal synthesis [15,17,18] and chemical vapor transport method [4,14,[19][20][21]. Using MBE, here we have studied the growth of Cr2Se3 thin 111)-(7×7) substrates.…”

“…Previously, chromium selenide systems have been studied to investigate their suitability as thermoelectric material for intermediate-temperature applications [10][11][12][13][14], intermediate temperature power generation [13], electrochemical sensors [15], etc. Several groups have studied the structural, magnetic, electrical and thermoelectric properties of single crystal Cr2+xSe3-x compounds grown using solid state reaction method [10][11][12][13]16], soft chemical and hydrothermal synthesis [15,17,18] and chemical vapor transport method [4,14,[19][20][21]. However, the studies focus mostly on the improvement in thermoelectric properties of transition-metal-doped bulk samples of Cr2Se3.…”