OPTICAL ENERGY-GAP VARIATION IN InAs–InSb ALLOYS

Abstract

Homogeneous samples of InAs–InSb alloys have been produced by very slow directional freezing and zone recrystallization methods, and used for the determination of values of the optical energy gap Eg by standard infrared transmission measurements. Room-temperature values of Eg have been obtained in the composition ranges 0–20 and 55–100 mol % InSb and the variation of Eg with temperature from 90 °K to 360 °K for alloys in the composition ranges 0–20 and 80–100 mol % InSb. Approximate room-temperature values of Eg for alloys in the range 20–55 mol % InSb have been obtained by diffuse reflectivity measurements on annealed powders.The value of Eg is found to fall as either compound is added to the other and the room-temperature values show a minimum of 0.10 eV at approximately 60 mol % InSb.