Cadmium Telluride - Applications

Applications

CdTe is used to make thin film solar cells, accounting for about 6% of all solar cells installed in 2010. They are among the lowest-cost types of solar cell, although a comparison of total installed cost depends on installation size and many other factors, and has changed rapidly from year to year. The CdTe solar cell market is dominated by First Solar. In 2010, around 1.5 GW_p of CdTe solar cells were produced; if this figure were massively increased, there might eventually be a shortage of tellurium, as Te is among the rarest elements in the Earth's crust (see below). Specifically, production could be expanded by a factor of 1000 to 10000 (estimates vary) before running out of Te. Another problem for the technology is the toxicity of cadmium, see below. For more details and discussion see cadmium telluride photovoltaics.

CdTe can be alloyed with mercury to make a versatile infrared detector material (HgCdTe). CdTe alloyed with a small amount of zinc makes an excellent solid-state X-ray and gamma ray detector (CdZnTe).

CdTe is used as an infrared optical material for optical windows and lenses but it has small application and is limited by its toxicity such that few optical houses will consider working with it. An early form of CdTe for IR use was marketed under the trademarked name of Irtran-6 but this is obsolete.

CdTe is also applied for electro-optic modulators. It has the greatest electro-optic coefficient of the linear electro-optic effect among II-VI compound crystals (r₄₁=r₅₂=r₆₃=6.8×10−12 m/V).

CdTe doped with chlorine is used as a radiation detector for x-rays, gamma rays, beta particles and alpha particles. CdTe can operate at room temperature allowing the construction of compact detectors for a wide variety of applications in nuclear spectroscopy. The properties that make CdTe superior for the realization of high performance gamma- and x-ray detectors are high atomic number, large bandgap and high electron mobility ~1100 cm2/V·s, which result in high intrinsic μτ (mobility-lifetime) product and therefore high degree of charge collection and excellent spectral resolution.