Identification and investigation of impurities in undoped Hg1−xCdxTe

The effect of impurities on electrical properties has been the most sought information for the well-known infrared sensing material mercury-cadmium telluride. The relationship between the excess holes (p-type) or excess electrons (n-type) of undoped mercury-cadmium tellurideHg_1?xCd_xTe(0.23 ? x ? 0.4)and the residual impurities in the crystals were investigated. The impurities in the undoped material were determined using emission spectrometry, atomic absorption, and spark sources mass spectrometry.Trace analysis indicates that impurities such as Cu and Ag consistently appear inp-type samples. Although these elements are not frequently observed inn-type substance, occasionally they are found in the material in a minute amount. Impurities such as Si, Cr, Pb, Li, Rb, Co, and Sn have been detected in bothp-type andn-type materials. The possible correlation of these impurities with thep-type orn-type behavior of the undoped material is discussed.