Alloy states in dilute GaAs1−xNx alloys (x&amp;lt;1%)

We investigate the electronic properties of GaAs1−xBix by photoluminescence at variable temperature (T=10–430K) and high magnetic field (B=0–30T). In GaAs0.981Bi0.019, localized state contribution to PL is dominant up to 150K. At T=180K the diamagnetic shift of the free-exciton states reveals a sizable increase in the carrier effective mass with respect to GaAs. Such an increase cannot be accounted for by an enhanced localized character of the valence band states, solely. Instead, it suggests that also the Bloch states of the conduction band are heavily affected by the presence of bismuth atoms.

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“…2, 8,9,18,19 This is also the case for GaAs 0.981 Bi 0.019 , whose PL spectra are shown in Fig. 1͑a͒ for different temperatures.…”

Section: Influence Of Bismuth Incorporation On the Valence And Conducmentioning

confidence: 79%

Influence of bismuth incorporation on the valence and conduction band edges of GaAs1−xBix

Pettinari

Polimeni

Capizzi

et al. 2008

Applied Physics Letters

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“…In GaAs 1-x N x , quite different results have been obtained in the most recent studies [35,39]. It appears that the PL peak, even under very high field (e.g., B > 30 T), might not actually originate from the band gap transition [35,40], due to the energy relaxation and the existence of various N related bound states. The results of using various other techniques, quantum confinement [6], ODCR on quantum well samples [17] and thermo-magnetic transport [18], are all subjected to further investigation as to what has really been measured.…”

Section: Electron Effective Mass In Gaas 1-x N Xmentioning

confidence: 80%

Effects of heavy nitrogen doping in III–V semiconductors – How well does the conventional wisdom holdfor the dilute nitrogen “III–V‐N alloys”?

Zhang

Fluegel

Hanna

et al. 2003

Physica Status Solidi (b)

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PACS 71.35.Cc, Although heavily N doped III-V semiconductors are frequently referred to as dilute nitrogen III-V-nitride alloys in general, it is important to realize that there are some subtle but important differences among them. In the indirect gap semiconductor GaP, since even a single N impurity can have a bound state, as far as the absorption near the band gap is concerned, it is difficult to describe GaP : N as an alloy. The N induced bound states (a hierarchy of impurity complexes) can in fact give rise to rather strong absorption below the indirect band gap, which effectively reduced the energy of the "absorption edge", but the position of the absorption edge cannot be defined in a conventional way. In the direct gap semiconductor GaAs, a single N impurity does not form a bound state but instead has a resonant state above the conduction band edge. In this aspect, GaAs : N is similar to the situation in a conventional alloy, say, GaAs : P, except that the perturbation of N to the host is much stronger than that of P. However, because in reality N incorporation is typically in a random manner and a cluster as small as one N pair can generate bound states, the permissible region for GaAs : N to behave as a regular alloy is in fact rather limited, i.e., only when the N concentration is low enough so that the N pair and cluster states do not significantly interact with the host. In this study, a precise tracking of the evolution of the host and N induced impurity states will be offered for the two prototype systems, GaAs : N and GaP : N, with x varying from as low as ~10 -5 to ~10-2. Such a study gives valuable insight to the underlying physics of the material evolution, sets up a bench-mark for testing the theoretical modeling of this type of system, and serves to enhance our understanding of the behavior of isoelectronic impurities in semiconductors in general. The dissimilarity between GaP : N and GaAs : N indicates that seeking a unified model for all the isoelectronic doping systems is unrealistic. Our study also indicates that for strongly perturbed systems like GaP : N and GaAs : N, certain materials properties could be less well defined or not uniquely defined, as compared to those in other conventional semiconductor alloys.

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“…Although only the 80 K data are presented in this paper, the PL line shapes at other temperatures ͑from 10 to 300 K͒ remain quantitatively the same as those of 80 K. The PL peaks below 1.55 eV labeled with cross ͑ϩ͒ symbols are from the recombination near the fundamental bandgap E 0 of GaAs 1−x N x . 16 The E 0 emission in GaAs 1−x N x ͑x Ͼ 0͒ exhibits an asymmetrical line shape with a highenergy tail as that observed in bulk GaAs. In addition to the E 0 peak, GaAs 1−x N x exhibits a broad luminescence band that extends a few hundred meV above E 0 together with some sharp Raman lines.…”

Section: Methodsmentioning

confidence: 99%

Photoluminescence from the nitrogen-perturbed above-bandgap states in dilute GaAs1−xNx alloys: A microphotoluminescence study

Tan

Luo

et al. 2006

Phys. Rev. B

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Using microphotoluminescence ͑-PL͒, in dilute N GaAs 1−x N x alloys, we observe a PL band far above the bandgap E 0 with its peak energy following the so-called E + transition, but with contribution from perturbed GaAs host states in a broad spectral range ͑Ͼ100 meV͒. This finding is in sharp contrast to the general understanding that E + is associated with a well-defined conduction band level ͑either L 1c or N x ͒. Beyond this insight regarding the strong perturbation of the GaAs band structure caused by N incorporation, we demonstrate that a small amount of isoelectronic doping in conjunction with -PL allows direct observation of above-bandgap transitions that are not usually accessible by PL.

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Alloy states in dilute GaAs1−xNx alloys (x<1%)

Cited by 24 publications

References 16 publications

Influence of bismuth incorporation on the valence and conduction band edges of GaAs1−xBix

Influence of bismuth incorporation on the valence and conduction band edges of GaAs1−xBix

Effects of heavy nitrogen doping in III–V semiconductors – How well does the conventional wisdom holdfor the dilute nitrogen “III–V‐N alloys”?

Photoluminescence from the nitrogen-perturbed above-bandgap states in dilute GaAs1−xNx alloys: A microphotoluminescence study

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