[en] In this paper, a model for the band gap energy of the N-rich GaNAs (0< x≤0.07) and the As-rich GaNAs (0.95< x≤1) is developed. For the N-rich GaNAs, The parameters describing the variation of the CBM and the VBM in the N-rich GaNAs are obtained by fitting the experimental data. For the As-rich GaNAs, the parameters in the model are obtained by fitting the experimental data of the band gap energy. It is found that the band gap evolution of the N-rich energy is different from that of the As-rich band gap energy. The model may be used to calculate the band gap energy of other dilute group III-N-V nitrides.

[en] Using first-principles method we studied the compensation mechanism of As donor in Hg_1-xCd_x Te based on the model Berding et al. (1998, 1999) of As_Hg-V_Hg pair. We show that the binding of As_Hg and V_Hg results from donor-acceptor coupling, and the compensation of As donor can be clearly explained in terms of electronic deactivation by V_Hg. The pairing physics derived from this study confirm the available theoretical and experimental results.

[en] The equilibrium between clusters and dopant in solution was studied on silicon on insulator specimens uniformly doped with As at concentrations C_As from 1 to 7.6x10²⁰cm^-3. The values of the carrier density n^* after equilibration at 700, 800, and 900 degree C are reported. With increasing dopant concentration n^* rapidly saturates to the limiting value of the carrier density n_e, thus simulating a precipitation process. It is shown that the values of n^* at different temperatures and dopant concentrations can be calculated by an equation derived in the Appendix by using a simple cluster model. The deactivation was analyzed by isothermal annealing of the specimens at temperatures in the range 550 - 800 degree C. At high temperature the kinetics accurately complies with the rate equation -dn/dt=A{exp[-(E-αn)/kT]-(n₀-n)/(n₀-n^*)exp[-(E-αn^*)/kT]} which is the one reported in [D. Nobili, S. Solmi, M. Merli, and J. Shao, J. Electrochem. Soc. 146, 4246 (1999)] complemented by the second term on the right to account for the declustering process. Deviations leading to rates lower than predicted by the above equation are presented by the most heavily doped compositions after partial deactivation at temperatures ≤ 700 degree C. The analysis of this phenomenon puts into evidence that clustering presents a limiting rate which only depends on temperature and carrier density, and is insensitive to As concentration. [copyright] 2001 American Institute of Physics

[en] The transient behavior of P diffusion in Si implanted with As or Ge above the amorphizing threshold has been investigated. Annealing at 720 degree C after Ge implantation induces extensive P segregation into the extended defect layer formed by implantation damage. This segregation is attributed to P trapping to end-of-range {311} defects and dislocation loops. For As implantation, P segregation was also observed only after 1 min annealing. However, in contrast to the Ge implantation, in the As-implanted samples, significant P depletion occurs in the As-tail region after further annealing. Nonequilibrium simulation that takes into account both Fermi-level and electric field effects shows the P depletion during transient enhanced diffusion. Furthermore, simulation results based on the coexistence of neutral and positively charged phosphorus-interstitial pairs agree well with the obtained experimental results. [copyright] 2001 American Institute of Physics

[en] The effects of As doping, at concentrations C_As≤4.8x10¹⁸cm^-3, on the growth kinetics of Si(001):As layers deposited at temperatures T_s=575--900^oC by gas-source molecular-beam epitaxy from Si₂H₆ and AsH₃ have been investigated. With constant AsH₃ and Si₂H₆ fluxes, film deposition rates R_Si increase while C_As decreases with increasing T_s. All incorporated As resides at substitutional electrically active sites for C_As up to 3.8x10¹⁸cm^-3 (T_s=800^oC), the highest value yet reported for Si(001):As growth from hydride source gases. Immediately following film growth or partial-monolayer As adsorption on clean Si(001), the samples were quenched to 300^oC and exposed to atomic deuterium (D) until saturation coverage. In situ D₂ temperature-programmed desorption (TPD) spectra from both as-deposited Si(001):As and As-adsorbed Si(001) layers are composed of β₁ and β₂ peaks, due to D₂ desorption from Si monodeuteride and dideuteride surface phases, together with a new peak β₃ which we attribute to desorption from Si--As mixed dimers. Analyses of the TPD spectra show that, because of the lone-pair electrons associated with each As surface atom, the total dangling-bond coverage, and hence R_Si, decreases with increasing incoming flux J_AsH3 at constant T_s. From measurements of the steady-state As surface coverage θ_As vs C_As and T_s, we obtain an As surface segregation enthalpy ΔH_s=-0.92eV. Dissociative AsH₃ adsorption on Si(001) was found to follow second-order kinetics with a relatively T_s-independent reactive sticking probability of 0.3. Associative As₂ desorption is also second order with a rate constant k_d,As2=1x10¹³exp(-3.0eV/kT_s). From the combined set of results, we develop a predictive model with no fitting parameters for C_As vs J_AsH3, J_Si2H6, and T_s

[en] It is experimentally proved that the presence of the temperature gradient (at the interface of the liquid and solid phases in heavily doped monocrystals of n-Si: As in the process of their growth from a melt) does not lead to an anisotropy in the fluctuating distribution of a doping impurity. This fact shows the dominating role of randomization in the spatial distribution of a doping impurity due to kT during the growth on n-Si doped monocrystals from a melt.

[en] According to the one-dimensional quantum state distribution, carrier scattering, and fixed range hopping model, the structural stability and electron transport properties of N-, P-, and As-doped SiC nanowires (N-SiCNWs, P-SiCNWs, and As-SiCNWs) are simulated by using the first principles calculations. The results show that the lattice structure of N-SiCNWs is the most stable in the lattice structures of the above three kinds of doped SiCNWs. At room temperature, for unpassivated SiCNWs, the doping effect of P and As are better than that of N. After passivation, the conductivities of all doped SiCNWs increase by approximately two orders of magnitude. The N-SiCNW has the lowest conductivity. In addition, the N-, P-, As-doped SiCNWs before and after passivation have the same conductivity–temperature characteristics, that is, above room temperature, the conductivity values of the doped SiCNWs all increase with temperature increasing. These results contribute to the electronic application of nanodevices. (paper)

[en] Highlights: • Both (1 × 2) and (2 × 1) reconstructed Si(1 0 0):As surfaces can be prepared by MOCVD. • In situ RAS enables detailed process control even at elevated temperatures. • Si:As surface reactions strongly depend on the Si(1 0 0) substrate misorientation. • Atomically flat low-offcut Si(1 0 0):As-(1 × 2) surfaces with regular double-layer steps. • Arsenic atoms are considered to replace Si atoms during the adsorption process. Low-defect III-V integration on Si(1 0 0) requires atomically well-ordered heterointerfaces. To this end, we study the interaction of As with Si(1 0 0) surfaces and the formation of dimerized Si(1 0 0):As surfaces in situ with reflection anisotropy spectroscopy during metalorganic chemical vapor deposition (MOCVD). Control of surface processes allows us to intentionally ‘rotate’ the dimer orientation and choose between predominantly (1 × 2) and (2 × 1) reconstructed Si(1 0 0):As surfaces both for low and higher surface misorientation. We also verify that the (2 × 1) surface reconstruction becomes energetically more favorable for vicinal Si(1 0 0):As surfaces. We explain the preparation of Si(1 0 0):As surfaces displaying an almost single-domain, (1 × 2) reconstructed surface with an RMS roughness ≤1 Å and exhibiting broad, atomically flat terraces as well as regular double-layer steps. This surface is highly suitable for subsequent low-defect III-V integration.

No abstract available

No abstract available