Band anti‐crossing and carrier recombination in dilute nitride phosphide based lasers and light emitting diodes

Abstract

We use high pressure techniques to investigate the properties of two classes of “dilute‐nitride‐phosphide”‐based devices; GaNP/GaP light emitting diodes for yellow–amber–red display applications and GaNAsP/GaP lasers, a potential route to producing lasers monolithically on silicon. Based upon high pressure electroluminescence measurements we find that the band anti‐crossing (BAC) model reasonably describes the GaN(As)P system based on an average of the nitrogen states. In terms of device characteristics, we find that carrier leakage into the X‐minima of GaP reduces the efficiency of GaNP/ GaP LEDs with increasing pressure. Lasing has been observed in GaNAsP/GaP devices with a pulsed threshold current density of 2.5 kA/cm2 at 80 K (λ = 890 nm). A weak increase in threshold current with hydrostatic pressure indicates that a carrier leakage path that does not involve the GaP X ‐minima is the dominant carrier recombination mechanism in these devices, in contrast to the LEDs. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

A theoretical investigation of the band alignment of type-I direct band gap dilute nitride phosphide alloy of GaN x As y P 1– x–y /GaP quantum wells on GaP substrates

“…The BAC model, based on the repulsion of a N-related level with the Γ level of the host material, has been widely used because of its simplicity and qualitative agreement with experimental observations, for example, the red shift of the band gap and the increase in the electron effective mass with increasing N concentration. The validity of the simple BAC model in describing GaP-based dilute nitride materials has been shown by Chamings et al [4,12] According to the BAC model, the different behavior between GaAsN and GaPN can be explained by the difference of the nature of the host material band gap (direct for GaAs and indirect for GaP) and the position of the N-related level relative to the conduction band (CB) (above the CB of GaAs and below that of GaP). [13,14] This simple model describes the effect of nitrogen incorporation in dilute nitrides and allows us to calculate the fundamental band gap.…”

“…[3] More recently, attention has turned to GaP based dilute nitrides where additional interesting phenomena and applications can also be explored. [4] Fortunately, there is a relatively small difference in the lattice constants of GaP and Si (less than 0.4% at room temperature), allowing the growth of GaP on Si without dislocations. [5] Although GaP is itself an indirect band gap semiconductor, the dilute nitride mixed compound Ga(NAsP) with a high As fraction exhibits a direct band gap material lattice matched to GaP and hence Si.…”

A growth diagram for chemical beam epitaxy of GaP1−xNx alloys on nominally (001)-oriented GaP-on-Si substrates

“…The incorporation of small amounts of N into GaP, besides decreasing the lattice parameter, induces an indirectto-direct band gap transition well described by the band anticrossing model [1,2]. Remarkably, for a N mole fraction = 0.021, the ternary compound GaP 1− N is latticematched to Si with a direct band gap of about 1.96 eV at room temperature, making this material rather unique for the monolithic integration of pseudomorphic red-light emitters and III-V photovoltaic solar cells with the widespread, highly scalable and cost-effective Si technology [3,4,5,6,7,8,9,10].…”

Carrier Recombination Dynamics Investigations of Strain-Compensated InGaAsN Quantum Wells

“…The use of strain-compensated InGaAsN QW with GaAsP barrier layers had resulted in very low threshold current density for laser devices emitting in the 1300-nm and 1400-nm spectral regimes [9], [10]. Though low-threshold current density devices have been realized for dilute-nitride lasers in the 1300-to 1400-nm spectral regime, several key issues still remain of great interest to improve the temperature insensitivity of the threshold current at elevated temperature, as well as to improve the understanding of the effect of nitrogen incorporation into the InGaAsN QW on the optical response of the materials [33]- [36]. The improved insight into the physical origin of optical transitions and their dynamics is important, as this can shed light onto the understanding on the mechanism for achieving efficient optical emission.…”