Properties of hybrid MOVPE/MBE grown GaAsBi/GaAs based near-infrared emitting quantum well lasers

Abstract

A combined growth approach involving both molecular-beam epitaxy and metal-organic vapor phase epitaxy has been developed to fabricate GaAsBi/GaAs-based quantum well (QW) laser structures with a Bi composition up to 8%. Lasing operation has been demonstrated at room temperature at 1.06 μm in laser diodes containing 3QWs that in turn contain approximately 6% Bi. A 5QW device demonstrated lasing at 1.09 μm at 80 K. Using temperature-and pressuredependent measurements of stimulated emission as well as pure spontaneous emission measurements, we show that the threshold current of the devices is limited by non-radiative defect-related recombination and an inhomogeneous carrier distribution. This is suspected to be due to inhomogeneity of the QW width as well as non-uniform Bi composition in the active region.

Novel Dilute Bismide, Epitaxy, Physical Properties and Device Application

“…Although Moussa et al reported that the PL intensity of GaAsBi enhances about one order of magnitude with an annealing temperature of about 700 • C [148], they suggested that the PL intensity improvement is dominated by the reduction of non-Bi-related defects [145]. Nevertheless, GaAsBi laser diodes [248,249] and LEDs [250] have been realized, suggesting the promising application of dilute bismides on optoelectronic devices.…”

Understanding and reducing deleterious defects in the metastable alloy GaAsBi

“…13 These defect-related issues have become a bottleneck in the successful applications of GaAsBi. For instance, to date, GaAsBi-based laser diodes require a threshold current density (2-10 kA cm − 2 ) 6,[14][15][16] that is approximately an order of magnitude higher than that of typical InGaAs-based laser diodes (0.2-0.5 kA cm − 2 ).…”

Electrically injected GaAsBi/GaAs single quantum well laser diodes

“…This can be explained by reabsorption effect when photons propagate along the device structure. 3 The FWHM of PL broadens to 124 meV at RT, which further proves the inhomogeneous broadening of the active layer. This inhomogeneous broadening effect has been observed for quantum dot lasers, which are representative examples of intensely inhomogeneous devices.…”

“…The threshold current (I th ) is 435 mA, giving a threshold current density (J th ) of 4.54 kA/cm 2 . Compared with the 1060 nm lasers grown jointly by MBE and MOVPE (J th =25 kA/cm 2 ), 3 the threshold current density is significantly reduced. This could be attributed mainly to the optimization of MBE growth, which effectively suppresses impurities and defects and reduces the non-radiative recombination center.…”

“…2 The incorporation of Bi will increase the spin-orbit split energy, which will be larger than the bandgap when the Bi composition in GaAsBi is approximately up to 10%. 3 Therefore, the hot-hole induced Auger recombination and the inter-valence band absorption can be suppressed, resulting in the enhancement of luminous efficiency and characteristic temperature. Such processes may potentially decrease the electrical power wasted as heat in a 1.55 µm laser chip.…”