Mercury cadmium telluride
![Energy gap as a function of cadmium composition.](/Images/godic/202501/26/HgCdTe_Eg_vs_x4708.PNG")
![A zincblende unit cell](/Images/godic/202501/26/Sphalerite-unit-cell-depth-fade-3D-balls4709.png")
![HgCdTe Bandgap in electron volts as a function of x composition and temperatureHgCdTe cutoff wavelength in µm as function of x composition and temperature.Relationship between bandgap and cutoff wavelength](/Images/godic/202501/26/Hgcdte_bandgap_x_t4709.png")
![](/Images/godic/202501/26/Hgcdte_cutoff_wavelength_x_t4709.png")
HgCdTe or mercury cadmium telluride (also cadmium mercury telluride, MCT, MerCad Telluride, MerCadTel, MerCaT or CMT) is narrow direct bandgap zincblende II-VI ternary alloy of CdTe and HgTe with a tunable bandgap spanning the shortwave infrared to the very long wave infrared regions. The amount of cadmium (Cd) in the alloy (the alloy composition) can be chosen so as to tune the optical absorption of the material to the desired infrared wavelength. CdTe is a semiconductor with a bandgap of approximately 1.5 eV at room temperature. HgTe is a semimetal, hence its bandgap energy is zero. Mixing these two substances allows one to obtain any bandgap between 0 and 1.5 eV.