The carrier blocking effect on 850 nm InAlGaAs/AlGaAs vertical-cavity surface-emitting lasers

Abstract

In this study, the carrier blocking effect on 850 nm InAlGaAs/AlGaAs vertical-cavity surface-emitting layers (VCSELs) was theoretically and experimentally investigated. By means of inserting a high-bandgap electron blocking layer, which was either 10 nm thick Al 0.75 Ga 0.25 As or 13 nm thick Al 0.9 Ga 0.1 As, on the p-side of a quantum-well active region, the laser output performance was theoretically found to be improved. VCSELs with and without an electron blocking layer were also experimentally demonstrated. It was found that the threshold current was reduced from 1.47 to 1.33 mA and the slope efficiency was increased from 0.37 to 0.53 mW mA −1 by inserting a 10 nm thick Al 0.75 Ga 0.25 As electron blocking layer. Also, the device became less sensitive to the device temperature, where the amount of increase in the threshold current at an elevated temperature of 95 • C was only 0.27 mA and the slope efficiency dropped by only 24.5%. A peak frequency response of nearly 9 GHz at 5 mA, measured from relative intensity noise (RIN), was obtained in these VCSEL devices.

Advances in high-power vertical-cavity surface-emitting lasers

“…For high-power VCSELs, there are serious carrier leakage effects contribute to thermal rollover in VCSELs [24]. Due to the exponential dependence on temperature, carrier leakage can severely damage device performance and accelerate the occurrence of thermal rollover.…”

“…The characteristics of light output and voltage versus current (L-I-V), threshold current and SE showed that VCSELs incorporating a high-bandgap Al 0.75 Ga 0.25 As layer exhibited greater stability within a substrate temperature range of 25 • C-95 • C [30]. National Chiao-Tung University conducted both theoretical and experimental investigations into the carrier blocking effect on 850 nm InAlGaAs/AlGaAs VCSELs [24]. Yun et al made further advancements by optimizing the energy band structure of quaternary AlGaAsSb [31].…”

High-Speed and High-Power 940 nm Flip-Chip VCSEL Array for LiDAR Application

“…We can observe that the flip-chip VCSEL with the GaAs substrate removal process has a higher slope efficiency (SE) and a larger roll-over current at 300 K and 360 K. This improvement can be attributed to the enhanced thermal dissipation of the flip-chip VCSEL. In addition, the carriers will escape from MQW when the injected current increases due to the increase in kinetic energy of carriers as the temperature rises [20][21][22]. As a result of this effect, slope efficiency and output power will be reduced.…”

Высокоскоростные Полупроводниковые Вертикально-Излучающие Лазеры Для Оптических Систем Передачи Данных (Обзор)

“…Для улучшения тепловых характеристик ВИЛ необходимо не только уменьшить последовательное сопротивление лазера, но и снизить уровень поглощения на свободных носителях и минимизировать тепловое сопротивление конструкции прибора. Кроме того, необходимо подавить выброс носителей из активной области при повышенной температуре (дополнительный вклад в токи утечки), что возможно за счет использования гетероструктур с раздельным огра-ничением носителей [46] и введения дополнительных потенциальных барьеров для электронов (carrier blocking layer) [92].…”