Characterization of silver selenide thin films grown on Cr‐covered Si substrates

Abstract

Thermal stability of silver selenide thin films formed from the solid-state reaction of Ag-Se diffusion couples on Si substrates covered with a thin Cr film, is investigated. Glancing angle X-ray diffraction (GXRD), XPS, atomic force microscopy (AFM) and Rutherford backscattering spectrometry (RBS) are used to characterize the as-deposited films and those annealed at 100, 200, 300, and 400• C. The results reveal the formation of polycrystalline orthorhombic silver selenide films that remain stable without compositional change upon thermal annealing, in marked contrast to the agglomeration exhibited by silver selenide films deposited on Si without Cr film. The improvement in the thermal stability is attributed to compressive stress relief by a grainy morphology with large surface area, the formation of which is promoted by partially oxidized Cr adhesion film.

Origins of Fermi-Level Pinning between Molybdenum Dichalcogenides (MoSe2, MoTe2) and Bulk Metal Contacts: Interface Chemistry and Band Alignment

“…Therefore, the core-level spectra obtained from MoTe (−134.9 kJ/mol) 54 is more positive than the ΔG°f ,Cr 2 Se 3 (−175.1 kJ/mol). 59 Cr completely reduces the MoSe 2 at the interface to form metallic Mo and CrSe x during the deposition in either UHV or HV (Figure 3a), which is chemically congruent to the Cr−MoS 2 interface detected in our previous work. 39 The chemical states detected in the Cr 2p, O 1s, and C 1s core-level spectra after Cr deposition on MoSe 2 in UHV and HV are also chemically congruent with those detected in the Cr−MoS 2 system discussed previously.…”

“…The formation of chromium selenide as a result of reactions between Cr and MoSe 2 is thermodynamically favorable considering the Δ G ° f,MoSe 2 (−134.9 kJ/mol) is more positive than the Δ G ° f,Cr 2 Se 3 (−175.1 kJ/mol) . Cr completely reduces the MoSe 2 at the interface to form metallic Mo and CrSe x during the deposition in either UHV or HV (Figure a), which is chemically congruent to the Cr–MoS 2 interface detected in our previous work …”

Achieving Ultrahigh Power Factor In n-type Ag2Se Thin Films By Carrier Engineering

“…The binding states of Ag and Se elements in the Ag 2.05 Se thin lm are investigated by XPS and the results are illustrated in Fig.4(b) and 4(c). As shown in Fig.4(b), the core level spectrums reveal that the sample have two strong peaks located at ~ 368.4 eV of Ag 3d 5/2 and ~ 374.2 eV of Ag 3d 3/2 , which agree with the spin-orbit phenomena of Ag and Ag + , respectively[40]. A broad peak ranging from 52 to 56 eV is observed and can be identi ed into two symmetric peaks to be assigned to Se 3d 5/2 and Se 3d 3/2 located at ~ 54.2 and ~ 54.9 eV, which is the characteristic shape of Se(− ) in a consistent bonding environment as shown in Fig.4(c)[40].…”

“…As shown in Fig.4(b), the core level spectrums reveal that the sample have two strong peaks located at ~ 368.4 eV of Ag 3d 5/2 and ~ 374.2 eV of Ag 3d 3/2 , which agree with the spin-orbit phenomena of Ag and Ag + , respectively[40]. A broad peak ranging from 52 to 56 eV is observed and can be identi ed into two symmetric peaks to be assigned to Se 3d 5/2 and Se 3d 3/2 located at ~ 54.2 and ~ 54.9 eV, which is the characteristic shape of Se(− ) in a consistent bonding environment as shown in Fig.4(c)[40]. Thus, these analyses indicate that the chemical states of the elements of the thin lms are Ag + and Se 2− , respectively.…”

Silver selenide nanoparticles: synthesis, characterisation and effect of preparation conditions under ultrasound radiation

“…To date, Ag 2 Se has been prepared by various methods, such as heating the mixture of the Ag and Se at high temperature [8], microwave radiation [9], hydrothermal [10], electrochemical route [11], sonochemical reaction [12], the use of a Ag 2 C 2 O 4 template utilising both anion-exchange and redox reactions [13], cation exchange reaction using water-dispersed ZnSe nanocrystals as precursors [14], the solid-state reaction of sequentially deposited Ag and Se [15] and pulse electrodeposition from a single aqueous solution of Ag and Se ions [16]. Many researchers have been exploring the simplest routes and the cheapest raw materials to obtain the most useful new materials under mild and non-toxic conditions.…”