Lateral carrier diffusion and surface recombination in InGaAs/AlGaAs quantum-well ridge-waveguide lasers

Abstract

We measured the increase in threshold currents due to lateral carrier diffusion in InGaAs/AlGaAs quantum-well ridge-waveguide laser diodes. The ridge stripes were fabricated by using both in situ monitored pure Cl2 reactive ion etching and selective wet etching to completely eliminate the spreading current in the conductive upper cladding layer while keeping the ridge sidewalls straight. After comparing the threshold data with a theoretical model, the ambipolar diffusion coefficient is found to be 22 cm2/s in the population-inverted InGaAs layer. This model is based on the calculated optical gain curve and the ambipolar carrier transport in the quantum-well and waveguiding layers. The dependence of carrier lifetime on the local carrier concentration is included in the calculation. Moreover, from another set of devices with the portions of the active layer outside the ridge stripes etched away, the surface recombination velocity is found to be around 1–2×105 cm/s.

Record performance of electrical injection sub-wavelength metallic-cavity semiconductor lasers at room temperature

“…A surface recombination velocity (SRV) of 5 × 10 4 cm/s is obtained through RE fitting. This value is lower than typical SRV of InGaAs structures produced by dry etching processes which is 1~2 × 10 5 cm/s [34,35], and approaches the lowest value reported to our knowledge [36]. In summary, we demonstrated record performance of a RT CW sub-wavelength metalliccavity semiconductor laser, comparable to conventional semiconductor lasers, thus achieving a long sought goal in such lasers.…”

A numerical method for the analysis of nonlinear carrier diffusion in cylindrical semiconductor optoelectronic devices

“…, the carrier density profile N is improved iteratively by obtaining N (1) , N (2) , N (3) , …, etc. At each iteration step, the carrier density profile of the previous step is used to define the matrix S. The iterations are continued till a suitable convergence in N is achieved.…”

“…The lateral transport of charge carriers, via diffusion and their loss through the above mentioned mechanisms in the plane of semiconductor quantum wells, play a crucial role in both the static as well as dynamic operations of semiconductor lasers [2]. Diffusion characteristics have been shown to affect the dynamic behavior, modulation response, mode dynamics and selection, beam quality, threshold current, etc.…”

“…Diffusion characteristics have been shown to affect the dynamic behavior, modulation response, mode dynamics and selection, beam quality, threshold current, etc. [2][3][4][5]. In order to overcome these problems, techniques such as chemical sidewall passivation, impurity induced disordering and semiconductor regrowth are used [5][6][7].…”

The influence of lateral carrier diffusion and surface recombination on the behavior of semiconductor optical amplifier (SOA)-based MMIs

“…The phenomena of lateral carrier diffusion and surface recombination, and their influence on the threshold properties of lasers, have been widely studied. These studies were mainly focussed on the modal gain change [7] and the induced antiguiding effect [8] due to these mechanisms. The self-imaging properties of an MMI are derived from a relationship between the propagation constants of the guided modes resulting from the lateral step-refractive index profile of the MMI waveguide.…”