Structural design optimization of 279 nm wavelength AlGaN homojunction tunnel junction deep-UV light-emitting diode

Abstract We demonstrated the structural optimization of AlGaN tunnel junction (TJ) deep-ultraviolet light-emitting diodes by changing the thickness and impurity concentrations of p + -type and n + -type AlGaN constituting the TJ. By decreasing the total thickness of the TJ to 23 nm, the operating voltage reached a minimum of 8.8 V at 63 A cm −2 . Further decrease in TJ thickness markedly increases the operating voltage. This finding implies that the depletion layer width becomes greater than the TJ thickness if it is smaller than 12 nm. Therefore, we conclude that the TJ thickness must be greater than the depletion layer width.