부산대학교 도서관

The electroluminescent characteristics of an InGaAsSb/GaAlAsSb heterostructure LED emitting at 1.85 μm are studied in the temperature range 20–200°C. It is shown that the emission power exponentially drops as P ≅ 0.4exp(2.05 × 103/T) with a rise in temperature primarily because of an increase in the Auger recombination rate. It is found that band-to-band radiative recombination goes in parallel with recombination through acceptor levels, the latter causing the emission spectrum to broaden. With a rise in temperature, the activation energy of the acceptor levels decreases by the law ΔE≅ 32.9 − 0.075T and the maximum of the LED’s emission spectrum shifts toward the long-wavelength range (hνmax = 0.693 − 4.497 × 10−4T). Based on the dependence Eg = hνmax − 0.5kT and experimental data, an expression is derived for the temperature variation of the bandgap in the In0.055Ga0.945AsSb active area, Eg ≅ 0.817 − 4.951 × 10−4T, in the range 290 K < T < 495 K. The resistance of the heterostructure decreases exponentially with rising temperature as R0 ≅ 5.52 × 10−2exp(0.672/2kT), while cutoff voltage Ucut characterizing the barrier height of a p−n junction decreases linearly with increasing temperature (Ucut = −1.59T + 534). It is found that the current through the heterostructure is due to the generation-recombination mechanism throughout the temperature interval.