Abstract:Surface-enhanced Raman scattering from crystal vibrational modes of a Sb film rather than from vibrational modes of individual molecules has been observed for the first time to our knowledge. A ~20x enhancement of the longitudinal-optical mode (150 cm(-1)) in the Raman spectra of crystalline Sb films deposited on silver-island films was obtained. The excitation profiles, as well as the dependence of Raman intensity on the thickness of Ag films, were studied.
“…Detailed parameters of each peak are listed in Table 1. The peak C at ~135 cm −1 and peak D at ~162 cm −1 attribute to mode of homopolar Sb-Sb bonds 28 and mode in Sb 2 Te 3 29 quintuple layers, respectively, which are the two basic components in the 9-layers ST unit of Sb 4 -(Sb 2 Te 3 ) 30 . The peak A at ~90 cm −1 and peak B at ~105 cm −1 result from mode of homopolar Te-Te bonds 31 and mode of homopolar Sb-Sb bonds 19 , respectively.Figure 3Temperature dependent Raman spectra of ( a ) ST and ( b ) AST films from 25 to 300 °C, respectively.…”
To date, the unpleasant trade-off between crystallization speed and thermal stability for most phase change materials is detrimental to achieve phase change memory (PCM) with both features of high-speed and good-retention. However, it is proved that Al doping in Sb2Te, served as storage media in PCM, favors both a high writing speed (6 ns) and a good retention (103 °C), as well as a low power consumption. Judging by experimental and theoretical investigations, doped Al atoms prefer to replace Sb in Sb2Te lattice, strongly bonded with 6 Te atoms, to form a homogeneous phase. While in amorphous Al doped Sb2Te (AST), Al atoms are in tetrahedral environment, firmly bonded with four Sb/Te atoms. The strong bonding in Al centered tetrahedron in amorphous AST can obstruct the collective motion of Sb atoms near the matrix boundary, leading to the improvement in thermal stability and the confinement in grain size.
“…Detailed parameters of each peak are listed in Table 1. The peak C at ~135 cm −1 and peak D at ~162 cm −1 attribute to mode of homopolar Sb-Sb bonds 28 and mode in Sb 2 Te 3 29 quintuple layers, respectively, which are the two basic components in the 9-layers ST unit of Sb 4 -(Sb 2 Te 3 ) 30 . The peak A at ~90 cm −1 and peak B at ~105 cm −1 result from mode of homopolar Te-Te bonds 31 and mode of homopolar Sb-Sb bonds 19 , respectively.Figure 3Temperature dependent Raman spectra of ( a ) ST and ( b ) AST films from 25 to 300 °C, respectively.…”
To date, the unpleasant trade-off between crystallization speed and thermal stability for most phase change materials is detrimental to achieve phase change memory (PCM) with both features of high-speed and good-retention. However, it is proved that Al doping in Sb2Te, served as storage media in PCM, favors both a high writing speed (6 ns) and a good retention (103 °C), as well as a low power consumption. Judging by experimental and theoretical investigations, doped Al atoms prefer to replace Sb in Sb2Te lattice, strongly bonded with 6 Te atoms, to form a homogeneous phase. While in amorphous Al doped Sb2Te (AST), Al atoms are in tetrahedral environment, firmly bonded with four Sb/Te atoms. The strong bonding in Al centered tetrahedron in amorphous AST can obstruct the collective motion of Sb atoms near the matrix boundary, leading to the improvement in thermal stability and the confinement in grain size.
“…In our work, this phonon mode is present in samples grown at 130 • C, which suggests that it can be due to some residual defects. 5a, after FLA sharp peaks appeared at about 115 cm −1 and 150 cm −1 indicating the presence of metallic Sb clusters [54] and a new peak at about 572 cm −1 caused by the out-of-plane vibration, namely the A 1 phonon mode. The RTA-treated SZO films feature new peaks at 582 cm −1 due to the E 1 in-plane vibration mode.…”
Zinc oxide (ZnO) is a wide bandgap semiconductor that holds significant potential for various applications. However, most of the native point defects in ZnO like Zn interstitials typically cause an n-type conductivity. Consequently, achieving p-type doping in ZnO is challenging but crucial for comprehensive applications in the field of optoelectronics. In this work, we investigated the electrical and optical properties of ex situ doped p-type ZnO films. The p-type conductivity has been realized by ion implantation of group V elements followed by rapid thermal annealing (RTA) for 60 s or flash lamp annealing (FLA) on the millisecond time scale in nitrogen or oxygen ambience. The phosphorus (P)-doped ZnO films exhibit stable p-type doping with a hole concentration in the range of 1014 to 1018 cm−3, while antimony (Sb) implantation produces only n-type layers independently of the annealing procedure. Microstructural studies of Sb-doped ZnO show the formation of metallic clusters after ms range annealing and SbZn-oxides after RTA.
The observed thickness dependence and excitation profiles of the surface-enhanced resonance Raman scattering (SERRS) from crystal violet (CV) on silver films demonstrated the importance of surface roughness and chemical effects. Using different normalization schemes in studying the excitation profile of SERRS we were able to identify that there are three multiplicative contributions to the observed overall enhancement, viz. the electromagnetic effect, the molecular resonance effect and the charge-transfer effect originating from the strong electronic interactions between CV and the metal islands.
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