Low-threshold SWIR GaSb-based MQW laser diodes enabled by optimized growth of active region

Abstract

SWIR optoelectronics has attracted attention for the potential applications such as laser radar, chemical sensing, and atmospheric window systems. Among suitable diodes for SWIR applications, Sb-based laser diodes (LDs) are ideal candidates due to their high-power efficiency, low threshold current density, and high-temperature stability. This work reports the low-threshold current density SWIR LD via detailed growth optimization of active region, which consists of InGaAsSb quaternary quantum wells (QWs). Firstly, optimal QWs growth temperature of 450 °C, a V/III ratio of 5, and an Sb cracker temperature of 700 °C for In0.24Ga0.76Sb QWs are identified with photoluminescence (PL) measurement. The optimized structure exhibited strong PL emission of ∼2.1 μm wavelength at room-temperature. As a result, the low-threshold current density SWIR InGaAsSb double-QWs LDs show a threshold current density of 125 A/cm², and a lasing spectrum of 2.08 μm, without AR/HR coatings and p-side down mounting. These LDs show diode performance comparable to state-of-the-art devices in terms of threshold current density. These results highlight the critical role of detailed growth control of QW active region in realizing low-threshold current density SWIR LDs.