Electroluminescence from the InGaN/GaN Superlattices Interlayer of Yellow LEDs with Large V-Pits Grown on Si (111)

Abstract

A blue emission originated from InGaN/GaN superlattice (SL) interlayer is observed in the yellow LEDs with V-pits embedded in the quantum wells (QWs), revealing that sufficient holes have penetrated through the QWs into SLs far away from the p-type layer. In the V-pits embedded LEDs, hole transport has two paths: via the flat 𝑐-plane region or via the sidewalls of V-pits. It is proved that the holes in SLs are injected from the sidewalls of V-pits, and the transportation process is significantly affected by working temperature, current density, and the size of V-pits. Four motion possibilities are discussed when the holes flow via the sidewalls. All these may contribute to a better understanding of hole transport and device design.

Effect of low-temperature GaN cap layer thickness on the optoelectronic performance of InGaN green LEDs with V-shape pits

“…As the current density increases to 7.5 A cm −2 , P3 appears at a shorter wavelength approximately Although P4 appears at higher current density compared to P3, its intensity increases much faster and even exceeds P3. In view of the possible luminous position of LEDs, we believe that P4 comes from InGaN/GaN SLs, as demonstrated in our previous work [24]. Furthermore, for the InGaN SLs, its indium composition is about 6% analyzed by the HRXRD.…”

Aging mechanism of GaN-based yellow LEDs with V-pits*

“…4(d), there are five directions for holes' injection: (I 1 ) injection into c-plane QWs through the flat c-plane region, (I 2 ) injection into c-plane QWs via the sidewall of V-pits, (I 3 ) injection into QWs of sidewall of V-pits and partaking in radiative recombination, (I 4 ) non-radiatively recombination at dislocations in V-pits, (I 5 ) injection through the sidewall of the V-pits and recombination in SLs radiatively. [22,23] According to the transport path of holes, P 1 is the main emission peak of the c-plane MQW, whose wavelength is around 550 nm at typical 35 A/cm 2 and shows a blue-shift with current density increasing. As for the shortwavelength emission, it can be seen clearly that P 2 appears at about 500 nm (35 A/cm 2 ) and P 3 with a shorter wavelength for about 445 nm (35 A/cm 2 ).…”

Influence of Superlattice Structure on V-Defect Distribution, External Quantum Efficiency and Electroluminescence for Red InGaN Based µLEDs on Silicon

“…A common problem discussed by researchers looking at red InGaN is the existence of parasitic emission at undesired wavelengths. Generally, this is blue emission, and much research has surrounded its origin and mitigation [23][24][25]. Unfortunately, there does not seem to be consensus about the origin or the nature of these blue peaks which may indicate that it's a complicated problem with a variety of potential sources and mitigation strategies.…”