Performance of 650 nm AlGaInP RCLEDs with different P-type DBRs

Abstract

Resonant cavity light-emitting diodes (RCLEDs) which composed of active region surrounded by two distributed Bragg reflector (DBR) mirrors have been reported in the communication system based on Plastic Optical Fiber (POF) and high brightness application. However, high performance of 650nm AlGaInP RCLED, which is strongly depends on the optimization of DBRs, especially the matched reflectivity between p-type and n-type DBR mirrors, is still difficult to obtain. In this paper, the performance of 650nm RCLEDs including 34-pair AlGaAs/AlAs n-type DBRs and different pairs of AlGaInP/AlInP p-type DBRs have been investigated both theoretically and experimentally. Top emitting chips with the size of 225×225μm 2 without encapsulation were fabricated under the same conditions, experimental results reveal that the device of optimized DBR mirrors with 10-pair p-type DBRs obtain high efficiency, low turn-on voltage and forward resistance, good temperature stability. INTRODUCTIONTraditional red LEDs suffered from poor extraction efficiency which is limited to 2 -4% by Snell's law. To solve this problem, different approaches have been developed, which can be separated into two categories. One is to optimize the device's geometry by texturing the surface of the chip, undercutting the sidewalls or changing the structures of geometries [1][2][3][4][5] , but these optimum structures may need complex processes or auxiliary structures; The other is concentrating on forcing the internal emission redirect into the escape cones and enhancing them, resulting in a modification of the spontaneous emission process, such that the internal emission is no longer isotropic, it results in improved extraction efficiency. This leads to the concept of the RCLED [6,7] , which is composed of a light-emitting active layer sandwiched between two mirrors forming a Fabry-Pérot (F-P) resonator.Resonant-cavity light-emitting diode (RCLED) is a novel light-emitting diode with high extraction efficiency. Since Schubert et.al [7] presented the first RCLED in 1992, the development of RCLED has been continuously increased in many applications, especially in the short-haul data communication system based on POF. The external quantum efficiency has been improved by optimizing the structure of RCLED, which can be up to 27% [8,9] , and the best simulated extraction efficiency has been reported over 40% [10] , by diminishing the loss of power in the unextractable modes.

Improved optical efficiency of GaAs-based infrared vertical-cavity surface-emitting laser enabled by combining a metallic reflector and a Bragg reflector

“…The reason for the lower series resistance of the developed VCSEL can be attributed to a thinner p-DBR applied in the developed VCSEL. 31,32 In addition, the I-V curve of the developed VCSEL with a combined reflector showed a lower increase rate than that of the conventional VCSEL. At 200 mA, the developed VCSEL with a combined reflector showed a lower voltage (2.0 V) compared with 2.2 V of the conventional one.…”

Fabrication and Characterization of GaN-Based Resonant-Cavity Light-Emitting Diodes with Dielectric and Metal Mirrors

“…For the three fabricated RCLED devices, the reflectivity is proper for light extracting from output mirror due to R 1 < R 2 . 20 Additionally, the output DBR mirror with higher reflectivity can increase G e and improve cavity enhancement of the extractable fields. For the RCLED device with the low top DBR reflectivity of 35%, the external quantum efficiency was a little low due to weak cavity effect.…”