TEMPERATURE-DEPENDENCE OF OPTICAL GAIN IN CDTE CDMNTE HETEROSTRUCTURES/

CdTe/CdMnTe graded index separate confinement heterostructures have be en used to produce visible laser emission under electronic or photo-pu mping. The optical gain of the structures has been measured as a funct ion of optical power and temperature. The maximum gain, about 190 cm-1 for a structure containing two quantum wells, is easily attained unde r excitation of about 6 kW/cm2 at 90 K. It decreases with increasing t emperatures, displaying two distinct regimes: (i) in the low temperatu re regime (below 200-250 K), the gain decreases exponentially with a c haracteristic temperature T0 = 110 K, and is interpreted as being due to the escape of holes from quantum wells and also to scattering of ca rriers by LO phonons; (ii) above 250 K, a faster decrease of gain take s place as a result of the thermal activation of carriers into the bar riers.