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Journal ArticleDOI

Recombination Emission in InSb

12 Aug 1966-Physical Review (American Physical Society (APS))-Vol. 148, Iss: 2, pp 873-885
TL;DR: In this article, the emission of phonon-assisted transitions is about 150 times weaker than that of direct transitions; this ratio is consistent with the strength of polar-mode coupling.
Abstract: Optically excited recombination emission has been studied for $n$- and $p$-type single-crystal samples of InSb at 77 and 4.2\ifmmode^\circ\else\textdegree\fi{}K. Emissions associated with band-to-band transitions, transitions with creation of an optical phonon, and transitions involving acceptor impurities have been observed. The band-to-band emission in the pure samples can be attributed to direct transitions, whereas the emission in samples of high donor concentrations clearly shows transitions violating wave-vector conservation. The emission of phonon-assisted transitions is about 150 times weaker than that of direct transitions; this ratio is consistent with the strength of polar-mode coupling. The $n$-type as well as the $p$-type samples show an emission band due to electron transitions from the conduction band to some impurity level at 7.5 meV above the valence band, and the emission is much more prominent in the Zn-doped samples. Germanium-doped $p$-type samples show a weak emission band associated with an acceptor level at 17 meV above the valence band. Samples of large donor concentrations show the effect of band tailing. The main impurity emission increases linearly while the band-to-band emission increased quadratically with the intensity of exciting light. From the shift and splitting of the emission under applied magnetic field, an electron effective mass of ${m}_{e}\ensuremath{\sim}0.018m$ and an electron $g$ factor of $|g|=40 \mathrm{at} 30$ kG are obtained. Electroluminescence has been observed in $p$-type crystals under pulsed electric fields of \ensuremath{\sim}60 V/cm. The observed spectrum appears to be a broadened impurity line. The emission is more than an order of magnitude weaker than optically excited emission corresponding to the same sample conductance.
Citations
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Journal ArticleDOI
TL;DR: In this paper, the infrared photoluminescence (PL) from InSb, InAs, and InAs1−xSbx (x < 0.3) epitaxial layers grown by atmospheric pressure organometallic vapor phase epitaxy has been investigated for the first time over an extended temperature range.
Abstract: Infrared photoluminescence (PL) from InSb, InAs, and InAs1−xSbx (x<0.3) epitaxial layers grown by atmospheric pressure organometallic vapor phase epitaxy has been investigated for the first time over an extended temperature range. The values of full width at half maximum of the PL peaks show that the epitaxial layer quality is comparable to that grown by molecular‐beam epitaxy. The observed small peak shift with temperature for most InAs1−xSbx epilayers may be explained by wave‐vector‐nonconserving transitions involved in the PL emission. For comparison, PL spectra from InSb/InSb and InAs/InAs show that the wave‐vector‐conserving mechanism is responsible for the PL emission. The temperature dependence of the energy band gaps, Eg, in InSb and InAs is shown to follow Varshni’s equation Eg(T)=Eg0−αT2/ (T+β). The empirical constants are calculated to be Eg0=235 meV, α=0.270 meV/K, and β=106 K for InSb and Eg0=415 meV, α=0.276 meV/K, and β=83 K for InAs.

277 citations

Journal ArticleDOI
A. A. Bergh1, P. J. Dean
01 Feb 1972
TL;DR: In this paper, a survey of prominent applications for various LEDs is presented, with an emphasis on the III-V semiconducting compounds and GaP LEDs in particular, including photometry, the physics of electrical injection and luminescence.
Abstract: Light-emitting diodes (LEDs) are devices designed to efficiently convert electrical energy into electromagnetic radiation, most of which is visible to the human eye. Some of the disciplines involved in the understanding and utilization of LEDs are reviewed, with emphasis on the III-V semiconducting compounds and GaP LEDs in particular. Salient features of photometry, the physics of electrical injection and luminescence, and the design of LEDs are discussed in detail, followed by a survey of prominent applications for the various LEDs.

258 citations

Journal ArticleDOI
Jagdeep Shah1
TL;DR: In this article, it has been shown that at relatively low intensities (5 W/cm 2 for GaAs) the photoexcited carrier distribution is Maxwellian with a carrier temperature T e different from the lattice temperature.
Abstract: It has become well established during the last few years that intense photoexcitation of a semiconductor leads to the heating of the carriers and the generation of nonequilibrium phonons. These phenomena which result from the relaxation of photoexcited carriers to the band extrema by interaction with other carriers and by emission of phonons, are reviewed in this paper. At relatively low intensities ( 5 W/cm 2 for GaAs) the photoexcited carrier distribution is Maxwellian with a carrier temperature T e different from the lattice temperature. T e as high as 150K and effective phonon temperatures as high as 3700K have been observed in GaAs. The observed variation of T e with excitation intensity leads to the conclusion that in semiconductors like GaAs the polar optical mode scattering is the dominant energy loss mechanism from the electron gas to the lattice. Similar results are obtained in CdSe and CdS. At higher intensities (>10 5 W/cm 2 for GaAs), the carrier dist0ribution becomes non-Maxwellian for reasons not well understood at present. We will also discuss some recent measurements of variation of T e with excitation wavelength and of the transmission spectra of photoexcited GaAs.

228 citations

Journal ArticleDOI
TL;DR: In this paper, an analysis is made of the theory of the luminescence spectra of semiconductors with direct optical transitions involving recombination of nonequilbrium carriers whose energies are close to the band gap edges.
Abstract: An analysis is made of the theory of the luminescence spectra of semiconductors with direct optical transitions involving recombination of nonequilbrium carriers whose energies are close to the band gap edges. The usual formulation of the theory of recombination is employed, i.e., given densities of free electrons and holes are assumed. The first part of the review is concerned with the luminescence (of the exciton, interband, impurity, or interimpurity type) of lightly doped semiconductors. Unsolved problems are noted and it is stressed particularly that the interband luminescence spectrum is governed largely by the interaction of carriers and by the mechanisms of their scattering, but in practice this has been ignored so far in the development of the theory and in the interpretation of the experimental results. The second (main) part of the review is devoted to the luminescence of heavily doped semiconductors. It is shown that the nature of the electron spectrum of such semiconductors, involving formation of density-of-states "tails" and broadening of the impurity levels, is manifested clearly in this case. It is stressed that the distribution of nonequilibrium carriers between localized states corresponding to a continuous spectrum is usually quite different from the quasiequilibrium distribution, i.e., it cannot be described by introduction of the quasi-Fermi level. An allowance for this circumstance makes it possible to explain a great variety of seemingly contradictory experimental data on the luminescence spectra of heavily doped semiconductors. The deviation of the carrier distribution from the quasiequilibrium case is manifested also in transient characteristics of the luminescence, and it also governs the characteristic features of radiative recombination in strongly compensated heavily doped semiconductors, which can be regarded as one of the models of amorphous semiconductors. It is pointed out in conclusion that the proposed concepts can account for the special features of the characteristics of electroluminescent structures made of heavily doped semiconductors.

180 citations

References
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Journal ArticleDOI
TL;DR: In this article, the effect of free carriers on the optical constants has been determined by using reflectivity and absorption measurements in the region 5 to 35 micron, and the significance of ${m}_{s}$ is considered for four different types of energy band structure.
Abstract: By using reflectivity and absorption measurements in the region 5 to 35 micron, the effect of free carriers on the optical constants has been determined for $n$- and $p$-type germanium, silicon, and indium antimonide, and for $n$-type indium arsenide. The contribution of the free carriers to the electric susceptibility is obtained from the optical constants. A carrier effective mass, ${m}_{s}$, is defined in terms of the susceptibility, and the significance of ${m}_{s}$ is considered for four different types of energy band structure. The experimental values of ${m}_{s}$ are compared with those calculated by using data from other experiments. Good agreement was found for $n$- and $p$-type silicon, $n$-type germanium, and $p$-type indium antimonide. In $p$-type germanium, the susceptibility due to transitions between the overlapping bands in the valence band was taken into account. However, the resulting ${m}_{s}$, for a sample of \ensuremath{\sim}${10}^{19}$ ${\mathrm{cm}}^{\ensuremath{-}3}$ impurity concentration, is larger by a factor of 1.8 than that calculated by using cyclotron resonance data. In $n$-type indium antimonide ${m}_{s}$ increases with carrier concentration. If one assumes ${m}_{s}$ to be energy-dependent, the shape of the conduction band calculated is consistent with previously reported measurements of the shift of the intrinsic absorption edge with electron concentrations. In the case of $n$-type indium arsenide, ${m}_{s}$ differs from the effective mass reported from thermoelectric measurements but gives good agreement with the values determined from the shift of the intrinsic absorption edge for an impure specimen.

590 citations

Journal ArticleDOI
TL;DR: In this paper, a simplified theory of the optical absorption and recombination radiation spectra due to direct transitions between hydrogen-like acceptor levels and the conduction band in a semiconductor with simple bands is given.

263 citations

Journal ArticleDOI
John J. Hopfield1
TL;DR: In this article, a tight-binding model was proposed to assign symmetry assignments of p valence bands and s conduction bands for ZnO and CdS on the basis of a tight binding model.

177 citations

Journal ArticleDOI
R. Newman1
TL;DR: In this article, the intrinsic absorption edge of $n$-type InP at 77\ifmmode^\circ\else\textdegree\fi{}K and 300\ifmode^''circ\decrease\text degree\fi {}K are reported.
Abstract: Measurements of the intrinsic absorption edge of $n$-type InP at 77\ifmmode^\circ\else\textdegree\fi{}K and 300\ifmmode^\circ\else\textdegree\fi{}K are reported. Differences are found in the spectra of samples of differing origin. The effects are believed due to impurities. Reflection and absorption spectra in the vicinity of the reststrahlen peak are shown. The reststrahlen wavelength is 30.5 \ensuremath{\mu}, the static and high-frequency dielectric constants are ${\ensuremath{\epsilon}}_{0}=15$ and ${\ensuremath{\epsilon}}_{\ensuremath{\infty}}=10.6$. Freecarrier absorption and reflection spectra are shown. A brief discussion of the implications of the various optical and electrical measurements as regards the conduction band structure is given.

80 citations