Abstract
Different size InGaN/GaN based micro-LEDs (μLEDs) are fabricated. An extremely high injection level above 16 kA/cm2 is achieved for 10 μm-diameter LED. The lateral current density and carrier distributions of the μLEDs are simulated by APSYS software. Streak camera time resolved photoluminescence (TRPL) results show clear evidence that the band-gap renormalization (BGR) effect is weakened by strain relaxation in smaller size μLEDs. BGR affects the relaxation of free carriers on the conduction band bottom in multiple quantum wells (MQWs), and then indirectly affects the recombination rate of carriers. An energy band model based on BGR effect is made to explain the high-injection-level phenomenon for μLEDs.
Highlights
The luminous efficiency have been achieved more than 300 lm/W, the efficiency droops appear disappointedly in the most excellent light emitting diodes (LEDs) under high injection level or high temperature [1,2]
Electroluminescence (EL) results show that 10 μm diameter LED can be well operated under current density above 16 kA/cm2, while the 300 μm one can only endure 226 A/cm2
Streak camera time resolved photoluminescence (TRPL) results show obviously that the decay rate is much faster for smaller size μLED because of less band-gap renormalization (BGR)
Summary
The luminous efficiency have been achieved more than 300 lm/W, the efficiency droops appear disappointedly in the most excellent light emitting diodes (LEDs) under high injection level or high temperature [1,2]. Few conventional LEDs can work for current densities in the order of hundreds of A/cm. Many remedies have been reported, such as double heterostructure (DH) active layer [4], polarization matched barriers and electron blocking layer [5, 6], nonpolar LED [7], GaN homogeneous epitaxy on freestanding substrate [8], improved hole injection [9], and so on. Some researchers have been achieved the current density more than 500 A/cm for nanorod LEDs with low efficiency droop [10]. The high cost nano-processing, point defects and self-heating may hinder these LEDs to practical application
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
