A review of high ideality factor in gallium nitride-based light-emitting diode

Abstract

Theory concerning the high ideality factor of gallium nitride (GaN) based light- emitting diode (LED) has been reviewed. The presence of a high ideality factor indicates a large forward voltage that results in efficiency reduction. The paper suggests that tunneling is the main reason defining the exponential behaviour of current-voltage measurements, which leads to a high ideality factor. However, there is also a paper that suggests that the design of current geometry in the LED chip defines the value of ideality factor. An effective current spreading geometry in the LED chip will minimize the ideality factor and make it fall between the ideal range of 1 to 2. Besides, how the ideality factor is calculated will also play a major role in defining its value. By calculating the ideality factor based solely on the radiative recombination current formula, the value of ideality factor can result in an ideal ideality factor of 1.08.