Accession Number : AD0430766


Title :   INFRARED ABSORPTION OF MG2 SN SINGLE CRYSTALS,


Corporate Author : AIR FORCE CAMBRIDGE RESEARCH LABS L G HANSCOM FIELD MASS


Personal Author(s) : Lipson,Herbert G


Report Date : Nov 1963


Pagination or Media Count : 36


Abstract : Infrared transmission and reflection measurements of n- and p-type semiconducting Mg2 Sn single crystals of different impurity concentrations were made between 2 and 30 microns at temperatures ranging from 18 to 296 K. At energies of 0.22 ev and above, the rapid increase in absorption is attributed to the intrinsic edge. From the energy dependence of absorption in the edge region, the mechanism of indirect transitions between the valence and conduction bands can be established. The energy axis intercepts of the straight lines representing phonon emission decrease with temperature, indicating a negative temperature variation of the absorption edge. A band in the 0.10 to 0.22 ev energy range present at all temperatures in n-type and above 196 K in p-type samples suggests transitions between two conduction minima separated by 0.162 ev at 18 K. The presence of a fundamental lattice vibration band has been indicated from transmission and reflection measurements at longer wavelengths. The absorption spectrum of Mg2 Sn is similar in character to those reported for other semiconducting intermettalic compounds of the II-IV series. (Author)


Descriptors :   *SEMICONDUCTORS , ABSORPTION , INFRARED SPECTRA , MAGNESIUM COMPOUNDS , TIN ALLOYS , SINGLE CRYSTALS , IMPURITIES , INFRARED PHENOMENA , INFRARED RADIATION , OPTICAL PROPERTIES


Distribution Statement : APPROVED FOR PUBLIC RELEASE