Tunable Surface Plasmon Resonance in Sn-Doped Zn–Cd–O Alloyed Nanocrystals

Abstract

Aliovalent ion doped n-type semiconductor nanocrystals (NC) have presently gained high interest in semiconductor research for their potential applications in plasmonics, transparent conducting oxide (TCO), and high speed optical device. For most of the cases the plasmonic absorbance band appears in the near infrared region (NIR) but it is rarely observed in visible wavelength for aliovalent ion doped semiconductor nanocrystals. In this article, we report the synthesis of Sn-doped ZnO monodispersed nanocrystals and their unique plasmonic absorbance property which is tunable from the visible to the NIR region (550 nm to >3000 nm) by varying the Sn dopant concentration and the degree of Cd-alloying. We have studied the surface enhanced Raman spectroscopy (SERS) of the 4-mercaptopyridine (4-MPy) molecule using Sn:ZnO NC thin film as SERS substrate and found a high enhancement factor value. A TCO thin film with a good figure of merit value has been prepared by Sn:Zn–Cd–O alloyed NCs by taking advantage of high electron density and high mobility of electrons of doped alloyed NCs. Application as SERS substrate and TCO are excellent features of Sn-doped Zn1–x Cd x O NCs.

A straightforward and “green” solvothermal synthesis of Al doped zinc oxide plasmonic nanocrystals and piezoresistive elastomer nanocomposite

“…Plasmonic semiconductor oxide nanocrystals such as Al-doped ZnO (AZO), [1][2][3] indium-doped ZnO (IZO), 3,4 Ga-doped ZnO (GZO), 3 Sn-doped In 2 O 3 (ITO), [6][7] Sb-doped SnO 2 (ATO) 8,9 or others [10][11][12][13][14] have attracted growing attention due to their applicability in many optoelectronic applications, such as nearinfrared selective electrochromic devices, 15 (flexible) displays 11 and polymer light emitting diodes. 4 They also demonstrate excellent bio-sensing and chemical sensing capabilities 16 .…”

Shape Controlled Plasmonic Sn Doped CdO Colloidal Nanocrystals: A Synthetic Route to Maximize the Figure of Merit of Transparent Conducting Oxide

“…[16,17] The plasmonic absorbance in WO 3−x arises for excess free electrons by self-doping due to oxygen vacancy. Tunable LSPR frequencies in NIR-mid-IR region have been explored in last five years by many researchers mainly focused on oxide based semiconductors like Gr III(B) [18][19][20] and Gr IV(A) doped ZnO, [21,22] Gr (III) doped CdO, [23][24][25][26][27] Sn doped In 2 O 3, [28] Nb doped TiO 2 , [29] Sb doped SnO 2 systems. [30] LSPR frequency (ω sp ) depends upon mainly bulk plasma frequency (ω p ) of nanoscale material which is in proportional relationship with free electron concentration.…”

“…[31] Thanks to high mobility of CdO among the other TCO which makes Sn doped Zn-Cd-O alloyed nanocrystals a promising TCO system as we have found in our earlier study. [21] Bulk crystal symmetry determines the shape tuning of material by controlling the growth of nanomaterials to achieve the anisotropic shape. [32,33] Lower symmetry structures are less likely to have equilibrium crystals of exotic shape.…”

Carrier concentration dependent optical and electrical properties of Ga doped ZnO hexagonal nanocrystals

“…4,5 In ZnO n-type doping naturally occurs due to native defects such as predominant oxygen vacancies due to the lowest formation energy during synthesis. [6][7][8][9][10][11][12] All possible types of vacancies and interstitial defects make ZnO the most attractive compound due to easily controllable relative concentration of various defects and tunable electronic properties. The spontaneous formation of high density vacancies and defects in ZnO generates a carrier concentration of 10 18 -10 19 cm À3 very close to Mott critical carrier density.…”