Luminescence efficiency of near-surface quantum wells before and after ion-gun hydrogenation

Chang, Ying‐Lan; Tan, I.‐H.; Zhang, Yong‐Hang; Merz, J. L.; Hu, Evelyn L.; Frova, A.; Emiliani, Valentina

doi:10.1063/1.109235

Cited by 33 publications

(30 citation statements)

References 10 publications

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“…Our assessment of passivation was linked to the enhanced photoluminescence of the hydrogen ion treated-QWI. Such an enhanced luminescence was found to be stable over a period of 3 years [6,7]. Based on numerous studies of those structures, using in situ Auger [8] and Temperature Programmable Desorption (TPD) [7], we believe that the role of the hydrogen ions is to react with excess arsenic in the material, removing it in the form of arsine.…”

Section: Introductionmentioning

confidence: 93%

Surface Passivation of Gaas-Based Phemt by Hydrogen Ion Irradiation

Shi

Chang

et al. 1996

MRS Proc.

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Surface passivation is a key issue in compound semiconductor device technology. The high density of surface states on unpassivated surfaces can lead to excessive non-radiative recombination at the surface, affecting optical devices, or provide leakage and low-field breakdown in electronic devices. Our previous studies on low energy, low-dose hydrogen ion treatment carried out at room temperature showed long-term improvement in the optical properties of near surface quantum wells. We have accordingly applied this process to GaAs-based pseudomorphic HEMTs (PHEMT) in order to improve their power performance. Although our process is designed so that the hydrogen reactions are confined to the surface of the substrate, a critical factor in the success of this treatment is the extent of in-diffusion of the hydrogen, and the possibility of dopant passivation. PHEMT structures were hydrogenated at various conditions and both Hall mobility and carrier density were monitored. For a low hydrogen ion dose (3 xl016 cm2 ) at 80 eV energy, some degradation of Hall mobility and carrier density was noted after the treatment, but full recovery of both parameters was achieved after a 400'C thermal anneal. Much higher hydrogen doses resulted in severe degradation of mobility and carrier density, which were only partially recovered after thermal anneal. Measurements on actual PHEMT devices showed an approximately 15% decrease in the transconductance, and in addition, a 60% decrease in the gate- 16-2to-drain leakage current after irradiation with 80 eV hydrogen ions at a dose of 3 xlO cm . The decrease of the leakage current indicates that passivation is taking place. The decrease of the transconductance suggests that hydrogen may be diffusing into the regions of the dopants. Optimization of the hydrogenation parameters should allow leakage reduction without sacrifice of transconductance.

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Section: Introductionmentioning

confidence: 93%

Surface Passivation of Gaas-Based Phemt by Hydrogen Ion Irradiation

Shi

Chang

et al. 1996

MRS Proc.

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“…The proximity of Q1 to the GaS/GaAs interface causes its intensity to diminish as the number of interface states increases. 18,19 These interface states act to pin the Fermi level and serve as centers for nonradiative recombination. Hence, 1 provides a measure of interface quality-the higher the value of 1 , the higher the interface quality.…”

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confidence: 99%

“…Previous work with similar samples has shown this event to be more probable than the capture of AlGaAs carriers into the GaAs QW. 18 Furthermore, it is worth mentioning that the diffusion of carriers away from Q1 may be influenced by band bending caused by the interface states. The spectra in Fig.…”

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confidence: 99%

Effect of initial surface reconstruction on the GaS/GaAs(001) interface

Pelzel

Nosho

Shoenfeld

et al. 1999

Applied Physics Letters

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We have used photoluminescence of a GaAs/Al0.3Ga0.7As near-surface quantum well structure to study the quality of the interface between GaAs and GaS deposited in ultrahigh vacuum (UHV) using [(tBu)GaS]4. In addition to the luminescence of the near-surface and the deep/reference quantum wells, luminescence was observed for the GaAs cap following the deposition of 100 Å of GaS. This additional feature demonstrates the high quality GaS/GaAs interface achievable through the UHV deposition of this precursor. The ratios of the integrated luminescence intensity of both the GaAs cap and the near-surface GaAs quantum well to the deep/reference quantum well indicate that there are fewer GaS/GaAs interface states for deposition on the Ga-rich GaAs(001)-(4×2)/(2×6) surface compared to deposition on the As-rich GaAs(001)-(2×4) surface. Furthermore, GaS passivated samples exposed to ambient conditions for eight months exhibit no luminescence degradation for the near-surface quantum well confirming that these films provide adequate passivation longevity.

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“…The importance of this effect in determining the emission efficiency has been demonstrated experimentally in various papers [1][2][3][4]. Recently we have proposed a quantitative model based on ambipolar tunneling of electrons and holes which is applicable to many-well systems in the bulk or single wells coupled to surface state [5].…”

mentioning

confidence: 99%

“…Inversely we can try to get information on the surface states by fitting experimental SM ARTICLE 739 photoluminescence data. We concentrate on the specific example of an Al Ga As surface with a nearby GaAs quantum well [1,6].…”

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confidence: 99%

Ambipolar tunneling in near-surface quantum wells

Emiliani

Frova

Presilla

1996

Superlattices and Microstructures

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We study the photoluminescence from a near-surface quantum well in the regime of ambipolar tunneling to the surface states. Under steady-state excitation an electric field develops self-consistently due to the condition of equal tunneling currents for electrons and holes. The field induces a Stark shift of the photoluminescence signal which compares well with experimental data from near-surface GaAs/AlGaAs single quantum wells.Comment: 8 pages, REVTeX 3.

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Luminescence efficiency of near-surface quantum wells before and after ion-gun hydrogenation

Cited by 33 publications

References 10 publications

Surface Passivation of Gaas-Based Phemt by Hydrogen Ion Irradiation

Surface Passivation of Gaas-Based Phemt by Hydrogen Ion Irradiation

Effect of initial surface reconstruction on the GaS/GaAs(001) interface

Ambipolar tunneling in near-surface quantum wells

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