Temperature dependence of optical gain in CdTe/CdMnTe heterostructures

Abstract

CdTe / CdMnTe graded index separate confinement heterostructures have been used to produce visible laser emission under electronic or photo-pumping. The optical gain of the structures has been measured as a function of optical power and temperature. The maximum gain, about 190 cm -1 for a structure containing two quantum wells, is easily attained under excitation of about 6 kW / cm 2 at 90 K. It decreases with increasing temperatures, displaying two distinct regimes: (i) in the low temperature regime (below 200–250 K), the gain decreases exponentially with a characteristic temperature T 0 = 110 K, and is interpreted as being due to the escape of holes from quantum wells and also to scattering of carriers by LO phonons; (ii) above 250 K, a faster decrease of gain takes place as a result of the thermal activation of carriers into the barriers.