Interface modification of two-step grown InGaN/GaN superlattices preparing layers for InGaN-based green LED on silicon substrate

摘要

In this paper, the influence of InGaN/GaN superlattices preparing layers (SPL) on the optoelectrical properties of InGaN/GaN green LED is investigated by a single or two-step growth of SPL. It is found that two-step growth of SPL leads to an abnormal turn-on behavior of such LED chips, accompanied by a drastically increased operating voltage and sharply degraded quantum efficiency. Interface modification by heavy Si-doping successfully solves the abnormal turn-on behavior and realizes a significantly enhanced wall-plug efficiency and lower operating voltage. The underlying physical mechanisms are discussed and analyzed theoretically by the simulation calculation.