Cadmium selenide (CdSe) appears as grayish-brown or red crystals, is insoluble in water, highly toxic, and has a melting point of 1350°C. It can be produced by co-heating metallic cadmium with hydrogen selenide and is used in electron emitters, spectral analysis, photoconductors, semiconductors, and photosensitive components.
3–12mm pieces (sintered), and -325 mesh 10μm or less with 99.999% purity; white to brown; cub or hexagonal crystal(s); hex: a=0.4309nm, c=0.7021 nm, enthalpy of fusion 305.307 kJ/mol; becomes red in sunlight; used as a red pigment, in semiconductors, and as an evaporation material and sputtering target to produce photoconductive films and infrared filters; possible use in the electrofabrication of microdiode arrays [HAW93] [MER06] [CER91] [KLE93] [KRE91]
The energy gap of the hexagonal CdSe obtained from the absorption measurement Eg (Γ6–Γ1 ) is Eg=1.84 eV, temperature coefficient -4.6×10-4 eV/K, and pressure coefficient 3.7×10-6 eV/kg–cm -2 .
The band structure of cubic CdSe is similar to that of GaAs.
In photoconductors, semiconductors, photoelectric cells, and rectifiers; in phosphors.
Dispersions with CdS (Aldrich products 208183, 217921) deposited on glass or Si substrates results in tunable red, yellow, or green fluorescent material.
Cadmium selenide is used as a n-type semiconductor and its nanoparticles are used in laser diodes, opto-electronic devices, nanosensing, biomedical imaging and high efficiency solar cells. Since, it is transparent to infrared light, it finds application in photoresistors and windows for instruments utilizing IR light.
ChEBI: Cadmium selenide is a cadmium molecular entity.
A single crystal can be grown artificially through the vapor phase method or the Stockbarger method.
To obtain evaporated films, the source materials are heated in the alumina crucible with a nichrome heater. Crystal with a larger grain size is obtained at a higher substrate temperature.
The following corrosives are reported:
HNO3 (water cleansing after 2–3 s)
H2SO4 (water cleansing after 5–10 s)
18 N solution of 30 HNO3:0.1 HCl:20 H2SO4 (40℃, 8 s, cleansing with concentrated H2SO4)
3 HCl:1 HNO3
Cadmium selenide is used as a photoconductive detector for λ: 0.3–0.72 mm (a sharp peak at 0.7 mm) at room temperature. The typical performances are as follows:
Peak detectivity: 2.1×1011 cm Hz1/2/watt, (λ: 0.7 mm)
Response time: ca. 12 ms
Intermittent frequency: 90 Hz
Dominant noise: current noise
CdSe crystal can exist in solid hexagonal or cubic structure. CdSe behaves as an n-type semiconductor, with a bandgap of 1.74 eV (300K).1
Flammability and Explosibility
Not classified
Structure and conformation
The space lattice of CdSe (Cadmium selenide) belongs to the two types of crystal system, the cubic system, with the zinc-blend type structure that has a lattice constant of a=0.605 nm, and the hexagonal system, with the wurtzite type structure that has lattice constants of a=0.430 nm and c=0.702 nm.
