Electroluminescence studies under forward and reverse bias conditions of a nitride-rich GaN 1− xP x SQW structure LED grown by laser-assisted metal-organic chemical vapor deposition

Abstract

We have fabricated a nitride-rich GaN 1− x P x single quantum well structure by laser-assisted metal-organic chemical vapor deposition. In the forward bias condition, the electroluminescence of the LED had two main peaks, of which the energy positions around 2.9 eV were called the blue-band and that around 2.2 eV were called the yellow-band. Further, the LED emitted in the yellow-band even during a reverse-bias condition. The peak energy of these emissions shifted toward higher energy as the drive current increased. The blue-band shift of increasing current may be explained by a band-filling mechanism, as reported for InGaN LEDs. The I– V characteristics of the LED are not very similar to those of the conventional InGaN LED. The component of current flow consists of an ohmic ingredient and an exponential ingredient. The equivalent ideal factor ( n) of this LED is over 200; also in the reverse bias region, the I– V curve has good linearity rather than an exponential component. These results suggest that blue-band emission relates to the exponential ingredient and the yellow-band emission relates to the ohmic ingredient.