Band engineering in dilute nitride and bismide semiconductor lasers

Abstract

Highly mismatched semiconductor alloys such as GaN x As 1−x and GaBi x As 1−x have several novel electronic properties, including a rapid reduction in energy gap with increasing x and also, for GaBiAs, a strong increase in spinorbit-splitting energy with increasing Bi composition. We review here the electronic structure of such alloys and their consequences for ideal lasers. We then describe the substantial progress made in the demonstration of actual GaInNAs telecomm lasers. These have characteristics comparable to conventional InP-based devices. This includes a strong Auger contribution to the threshold current. We show, however, that the large spin-orbit-splitting energy in GaBiAs and GaBiNAs could lead to the suppression of the dominant Auger recombination loss mechanism, finally opening the route to efficient temperature-stable telecomm and longer wavelength lasers with significantly reduced power consumption.

Impact of alloy disorder on the band structure of compressively strained GaBixAs1−x

“…This is of significant potential benefit for telecommunication lasers, because it could enable the suppression of the Auger recombination losses which dominate the threshold characteristics of GaInAsP and AlGaInAs lasers. 5,7,10 The strong band gap bowing in GaBi x As 1−x is similar to that observed in GaN x As 1−x , where E g decreases by as much as 150 meV when 1% of As is replaced by N. The band gap reduction in GaN x As 1−x has been well explained using a band-anticrossing (BAC) model. 11 It is well established that replacing a single As atom by N introduces a resonant defect level above the conduction band edge (CBE) in GaAs.…”

“…This crossing is technologically important for the design and realization of photonic devices, due to the possibility of suppressing at higher bismuth concentrations the CHSH Auger recombination loss process, whereby a Conduction band electron recombines with a Heavy-hole exciting a second hole into the Spin orbit band from the Heavy-hole band. 5,7,10 …”

“…[5][6][7][8] When a small fraction of As is replaced by Bi in GaAs, the energy gap E g decreases rapidly, by ≈90 meV when 1% of As is replaced by Bi. In addition, photoreflectance measurements show that the energy separation, SO , between the spin-split-off valence band and the valence band edge also increases rapidly with Bi composition.…”

Simulations of mid infrared emission of InAsN semiconductors

“…‫ܧ‬ ே is the position of the nitrogen impurity level, ܸ ே is the interaction potential and ‫ݔ‬ is the nitrogen composition. For dilute nitride ‫ݏܣ݊ܫ‬ ଵି௫ ܰ ௫ , the following values can be taken for the parameters ܸ = 2.0ܸ݁ [3] and the position of the Nitrogen impurity, ‫ܧ‬ ே = 1.44ܸ݁ [26][27]. The temperature dependent band gap of the host matrix (InAs) follows the Varshni formula [28][29][30];…”

GaAs-based dilute bismide semiconductor lasers: Theory vs. experiment

“…The incorporation of > 10% Bi produces a band structure in which ∆ SO > E g , which offers the possibility to suppress the non-radiative (Auger) recombination and intervalence band absorption loss mechanisms which dominate the threshold current and degrade the temperature stability of conventional InP-based QW lasers operating at telecommunication wavelengths [3].…”