Injection and Avalanche Electroluminescence of $hbox{Al}_{hbox{0.1}} hbox{Ga}_{hbox{0.9}} hbox{N/Al}_{hbox{0.15}} hbox{Ga}_{hbox{0.85}} hbox{N}$ Multiple Quantum Wells

摘要

Three periods of $hbox{Al}_{{rm 0}{rm .1}} hbox{Ga}_{{rm 0}{rm .9}} hbox{N/Al}_{{rm 0}{rm .15}} hbox{Ga}_{{rm 0}{rm .85}} hbox{N}$ multiple quantum wells (MQWs) were used as the active region of a p-i-n diode fabricated on 6 H-SiC substrate. Electroluminescence (EL) of these MQWs has been investigated in both injection and avalanche modes. Band-to-band luminescence of the $hbox{Al}_{{rm 0}{rm .1}} hbox{Ga}_{{rm 0}{rm .9}} hbox{N}$ wells was found to peak at 364 nm in the injection mode and in the range of 364–372 nm in the avalanche mode. The most striking phenomenon is that band-to-band EL of the $hbox{Al}_{{rm 0}{rm .15}} hbox{Ga}_{{rm 0}{rm .85}} hbox{N}$ barriers has also been observed in the injection mode, while it is not seen in the avalanche mode. This is explained by considering different sources of carriers and different carrier transportation mechanisms in the two modes. The luminescence intensity $I_{{rm EL}}$ has a power-law dependence on the current $I$ by $I_{{rm EL}} propto I^{rm 2}$ in the injection mode and by $I_{{rm EL}} propto I^{rm 4}$ in the avalanche mode.