OPTICAL-ACTIVITY IN THE VACANCY ORDERED III2VI3 COMPOUND SEMICONDUCTOR (GA0.3IN0.7)(2)SE-3

Great optical activity is realized by a vacancy ordered III2VI3 compou nd (Ga0.3In0.7)(2)Se-3 with point group 6 which is based on wurtzite s tructure and characterized by the screw arrangement of cation atoms al ong the c axis, The transition of the fundamental absorption edge is d irect and the band gap is estimated to be 2.05 eV. An anomalous optica l rotatory dispersion around the absorption edge is observed and the m aximum rotatory power of 125 degrees/mm is obtained at lambda=620 nm. The optical activity for red light is always above 60 degrees/mm, that is 4-6 times as large as that of ct quartz. (Ga0.3In0.7)(2)Se-3 singl e crystal is very useful, especially for the He-Ne laser as an optical ly active substance; the rotatory power reaches 103 degrees/mm, being more than 5 times of alpha quartz. (C) 1995 American Institute of Phys ics.