Mechanism of radiative recombination in the region of interband transitions in Si-Ge solid solutions

The electroluminescence of Si-Ge diodes (with a Ge content of 5.2% in the corresponding solid solutions) in the region of interband transitions has been studied at the temperatures T = 82 K and 300 K. The emission spectra, the linear dependence of the electroluminescence intensity on current, and the exponential decay of the intensity suggest an exciton mechanism of radiative recombination with and without the involvement of phonons during radiative transitions.     

Heat exchange at the bottom of a dead end bathed by a laminar impinging jet

The local and average heat exchange of a round laminar jet flowing perpendicularly onto the center of the bottom of a dead-end chamber are investigated numerically.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 51, No. 1, pp. 23–26, July, 1986.     

Epitaxially Grown Monoisotopic Si,Ge, and Si<Subscript>1–<Emphasis Type="Italic">x</Emphasis> </Subscript>Ge<Subscript> <Emphasis Type="Italic">x</Emphasis> </Subscript> Alloy Layers: Production and Some Properties

The technology of the growth of Si, Ge, and Si_1–xGe_x layers by molecular-beam epitaxy with the use of a sublimation source of monoisotopic ³⁰Si or ²⁸Si and/or gas sources of monogermane ⁷⁴GeH₄ is demonstrated. All of the epitaxial layers are of high crystal quality. The secondary-ion mass spectroscopy data and Raman data suggest the high isotopic purity and structural perfection of the ³⁰Si, ²⁸Si, ⁷⁴Ge, and ³⁰Si_1–x⁷⁴Ge_x layers. The ³⁰Si layers doped with Er exhibit an efficient photoluminescence signal.     

Some challenging points in the identification of defects in floating-zone <Emphasis Type="Italic">n</Emphasis>-type silicon irradiated with 8 and 15 MeV protons

Electrical properties of defects formed in n-Si(FZ) following 8 and 15 MeV proton irradiation are investigated by Hall effect measurements over the wide temperature range of T ≈ 25 to 300 K. Close attention is paid to the damaging factor of proton irradiation, leaving aside passivation effects by hydrogen. The concept of defect production and annealing processes being accepted in the literature so far needs to be reconsidered. Contrary to expectations the dominant impurity-related defects produced by MeV protons turn out to be electrically neutral in n-type material. Surprisingly, radiation acceptors appear to play a minor role. Annealing studies of irradiated samples of such complex defects as a divacancy tied to a phosphorus atom and a vacancy tied to two phosphorus atoms. The latter defect features high thermal stability. Identification of the dominant neutral donors, however, remains unclear and will require further, more detailed, studies. The electric properties of the material after proton irradiation can be completely restored at T = 800°C.     

Composition inhomogeneity and structural defects in Czochralski grown Ge<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>Si<Subscript>1 − <Emphasis Type="Italic">x</Emphasis></Subscript> solid solution crystals

The relationship between the plastic strain and the inhomogeneity of germanium distribution in single crystals of Ge _x Si_{1 ? x} (x = 4–9 at %) solid solutions grown using the Czochralski method has been studied. It is established that plastic straining develops via the nucleation of dislocations at their sources occurring in the Ge segregation bands, while the inhomogeneous profile of Ge distribution across the growth direction is caused by thermoelastic stresses.     

Stimulated Terahertz Emission of Bismuth Donors in Uniaxially Strained Silicon under Optical Intracenter Excitation

Semiconductors - The results of the experimental observation of stimulated terahertz emission under optical intracenter excitation of uniaxially strained bismuth-doped silicon are presented....