The size and temperature effect of ideality factor in GaN/InGaN multiple quantum wells micro‐light‐emitting diodes

Abstract

In this paper, the GaN/InGaN multiple quantum wells (MQWs) microlight-emitting diode (micro-LED) devices of different size with green light emission were fabricated. The ideality factor of micro-LED was discussed. For temperature-dependent electrical characterization, the current-voltage relationship within a temperature category of 303-573 K was measured. The contact resistance between electrodes and GaN was exhibited, and a favorable ohmic contact was achieved for p-electrode and p-GaN. Next, the temperature

Analysis of size dependence and the behavior under ultrahigh current density injection condition of GaN-based Micro-LEDs with pixel size down to 3 μm

“…In the injection current density of 0.1 A cm −2 , which can reach the most appropriate luminance for wearable display and head-up display functions, the shunt and series resistance were neglected, diffusion and recombination current in the space-charge region effectively influence the value of ideality factor. It is widely believed the n closed to 2 illustrates the recombination current is dominant in current transport mechanism, and most literature reported the n value between 1.5-2.0 or above 2.0 as well [24,29,[32][33][34]. Whereas figure 4(a) showed an obvious range for n blow 1.5, and the detailed evidence demonstrated all sizes Micro-LED could obtain the lowest n even <1.4 (such as 1.34 for 3 µm, 1.24 for 8 µm and 1.31 for 50 µm) in figure 4(b), indicating our devices were diffusion current dominated instead of recombination current dominated and reached an advanced electrical performance.…”

P‐10.13: Exploring the Temperature Dependence of GaN‐on‐GaN Homoepitaxy Micro‐LEDs

“…The reliability of micro-LEDs devices is closely related to the ideal factor, which can reflect the ratio between the diffusion current and the recombination current in the p-n junction [15]. In fact, the typical ideality factor for GaN-based LED is much larger than 2 due to the junction superposition [16], current crowding [17] and tunneling current in active region as well [18]. Ideal factor can be calculated by the following equation:…”

3.3: Higher External Quantum Efficiency with Lower Current Density Injection of <10 μm Pixel Size Arrays for Display Application

“…It can be clearly seen that the curves exhibited two regions after turn-on. The first region is the Shockley model region, where the Micro-LED electrical performance can be interpreted by ideal diode model at lower current density injection when the depletion region width is much smaller than diffusion length, and the ideality factor in this region is ideally between 1 and 2 according to our previous research [7]. In fact, the different depletion region width for various sizes will affect the current injection efficiency as well, which will be discussed in the capacitance-voltage characterization part.…”