Temperature Droop Characteristics of Internal Efficiency in $\hbox{In}_{x}\hbox{Ga}_{1-x}\hbox{N/GaN}$ Quantum Well Light-Emitting Diodes

The temperature droop characteristics of internal efficiency (IE) in InGaN/GaN quantum well (QW) structures were investigated using the multiband effective mass theory. In the case of a relatively small Auger recombination
$(<\ C_{A} = 5 \times 10^{-30}\ \hbox{cm}^{6}\hbox{s})$
, the QW structure with a smaller In composition
$(x = 0.1)$
shows a larger hot/cold factor (
$\hbox{IE}_{T_{1}}/\hbox{IE}_{T_{2}}$
, with
$T_{1}\ >\ T_{2}$
) than that with a larger In composition
$(x = 0.3)$
because the radiative recombination is dominant and the IE of the former is much larger than that of the latter. The hot/cold factors for QW structures with
$x = 0.1$
and 0.3 are 0.85 and 0.71 at
$J = 100\ \hbox{A/cm}^{2}$
, respectively. On the other hand, in the case of a relatively large Auger recombination
$(>\ C_{A} = 10^{-28}\ \hbox{cm}^{6}\hbox{s})$
, the hot/cold factor (0.69) of the QW structure with a larger In composition is found to be larger than that (0.62) with a smaller In composition. This is attributed to the fact that the Auger recombination is dominant even for the QW structure with a small In composition and that the difference of the IE between two different temperatures decreases with increasing
$x$
.