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The reverse leakage characteristics of AlGaNbased ultraviolet light-emitting diodes fabricated on sapphire substrate are studied by temperature-variable current–voltage(I–V)measurement from 300 to 450 K.At low-reverse bias range(0–0.5 V),the reverse leakage current exhibits tunneling characteristics.Meanwhile,under a more negative reverse bias range([0.5 V),the log(I)–log(V)plots exhibit close-to-linear dependency,which is in good agreement with the transport mechanism of space-charge limited current.A phenomenological leakage current model focusing on electron transmission primarily through continuous defect band formed by linear defects like dislocations is suggested to explain the reverse current–voltage characteristics.
The reverse leakage characteristics of AlGaN based ultraviolet light-emitting diodes fabricated on sapphire substrates are studied by temperature-variable current-voltage (I-V) measurement from 300 to 450 K. At low-reverse bias range (0-0.5 V), the reverse leakage current exhibits tunneling characteristics. Meanwhile while under a more negative reverse bias range ([0.5 V), the log (I) -log (V) plots exhibit close-to-linear dependency, which is in good agreement with the transport mechanism of space-charge limited current. A phenomenological leakage current model focusing on electron transmission formed through continuous defect band formed by linear defects like dislocations is suggested to explain the reverse current-voltage characteristics.