In recent years, molecular beam epitaxy (MBE) has become widespread because of its ability to stack up layers of different alloy composition. This allows simultaneous detection at several wavelengths. Furthermore, MBE, and also MOVPE, allow growth on large area substrates such as CdTe on Si or Ge, whereas LPE does not allow such substrates to be used. The advancement of crystal growth technology has proceeded deliberately and steadily for four decades in spite of the high vapor pressure of Hg at the melting point of HgCdTe and the known  toxicity of the material.