II-VI compounds

Wide Band Gap Chalcogenide Semiconductors

“…However, MgCh have larger band gaps than the other binary chalcogenide semiconductors mentioned here, so development of a stable synthesis pathway could be useful. The experimentally reported band gaps of MgS (ZB), MgS (WZ), MgSe (ZB), MgTe (ZB), and MgTe (WZ) have been estimated from MBE grown Zn 1– x Mg x (S,Se,Te) and Cd 1– x Mg x Te alloy films to be ∼4.5 (measured at 77 K), 4.87 (measured at 77 K), ∼3.6–4.05, ∼3.5, and ∼3 eV, respectively. ,, Considering their wide band gaps and structural compatibility with other II–VI compounds, MgCh usually act as a critical component in various alloy structures and enable tuning of properties (see Figure ). For example, alloying MgS with PbS in Pb 1– x Mg x S can allow for tunable morphology, transparency, band gap, and conductivity .…”

“…MnS is a wide-gap semiconductor that can crystallize in the WZ (γ) structure with a gap of 3.88 eV, in the ZB (β) structure with a gap of 3.8 eV in single crystal samples, rocksalt (α) with a gap of 2.8–3.2 eV and single crystal mobility of 10 cm 2 V –1 s –1 (the most stable phase at ambient conditions), and in an amorphous phase with a gap of 2.8–3.0 eV . MnS is intrinsically p-type, likely due to doubly ionized V Mn , with a low room temperature reported conductivity of ∼10 –5 S cm –1 , and MnS has been doped by, for example, Cd Mn .…”

“…Polycrystalline thin films can be prepared by sputtering, chemical bath deposition (CBD), and thermal evaporation, among other methods, and tend to have a mixed WZ and ZB structure with band gaps of approximately 2.3–2.5 eV. This variation has been explained by the range of substoichiometric sulfur content in reported films because of various deposition temperatures. , WZ CdS is typically grown n-type, and is ambipolar with nearly intrinsic electron conductivity of 2.8 × 10 –2 S cm –1 and nearly intrinsic hole conductivity of 1.5 × 10 –2 S cm –1 …”

“…(a) N-type conductivity and Hall-derived carrier concentration, (b) electron mobility, and (c) absorption coefficient of wurtzite (“hex”) CdS as a function of measurement temperature. Figures are from the Semiconductors: Data Handbook (pp 808 and 810) . Reproduced with permission from ref .…”

Synthesis and Near-Infrared Emission of Yb-Doped Cs2AgInCl6 Double Perovskite Microcrystals and Nanocrystals

“…and III–V (InP, GaAs, etc.) ones possess tetrahedral coordination around the metal ion. , Prior literature suggests that Yb 3+ and other trivalent lanthanides (Ln 3+ ) prefer octahedral or higher coordination environments . This becomes a major reason that recently, Ln 3+ -doping remained successful in APbX 3 perovskites, − unlike difficulties reported in doping other semiconductors with tetrahedral coordination environments. − The choice of Yb 3+ among other Ln 3+ is driven by the fact that Yb 3+ has one of the simplest valence f–f energy level structures involving only two states 2 F 5/2 and 2 F 7/2 separated by an energy gap of ∼992 nm (1.25 eV), resulting into intense NIR luminescence .…”