This paper briefly describes our work and the results on the growth of several III-V epitaxial semiconductor materials in high purity form by liquid phase epitaxy (LPE) technique. Various possible sources of impurities in such growth are listed and step-by-step procedures adopted to reduce them are discussed in particular reference to the growth of GaAs layers. The technique of growing very high purity layers by treating the melt with erbium is described for the growth of InGaAs and GaSb layers. © Indian Academy of Sciences.

S DHAR

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University of Calcutta (informally known as Calcutta University or CU) is a collegiate public state university located in Kolkata, West Bengal, India.&nbsp;Within India it is recognized as a &quot;Five-Star University&quot; and accredited &quot;A&quot; Grade by National Assessment and Accreditation Council.

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University Of Calcutta

Growth of high purity semiconductor epitaxial layers by liquid phase epitaxy and their characterization

Bulletin of Materials Science

Hall mobility and carrier concentration measurements are done on In0.53Ga0.47As layers grown by liquid phase epitaxy from melts containing 0.1-0.18 wt % Er. The carrier concentration in the layer decreased to 2 x 1014 cm-3 upon the addition of 0.16 wt % Er to the growth melt but the corresponding mobility of the layer increased only marginally. A detailed analysis of the temperature-dependent Hall mobility data for the samples using a theoretical curve fitting technique revealed that the donor impurities in the material are reduced to a greater extent compared to the acceptors, making the layers compensated. The experimental mobilities are further compared with the published values of theoretically calculated mobilities for InGaAs with similar compensations. It is shown that the space charge scattering effects are to be considered in order to get a good agreement between the experimental and the theoretical values. © 2000 American Institute of Physics.

Applied Physics Letters

Impurity reduction in In0.53Ga0.47As layers grown by liquid phase epitaxy using Er-treated melts

Detailed properties of In0.53Ga0.47As layers grown by liquid phase epitaxy from melts containing 0.04 and 0.1 wt % Er are reported. The carrier concentration in the material is reduced by almost two orders of magnitude as a result of Er doping. Low temperature photoluminescence measurements indicate that both the donor and the acceptor type impurities are gettered by Er and the full-width at half-maximum of the major peak is reduced to 4 meV for the layer with the highest Er doping. From deep level transient spectroscopy experiments on undoped layers, we confirm the presence of an electron trap with activation energy of 0.17 eV. Density of this trap is reduced by more than two orders of magnitude in the Er doped material and another electron trap with activation energy of 0.15 eV is revealed from the analysis of the experimental data. We associate the 0.17 eV trap with impurities in the material. From low temperature photoconductivity and photocapacitance experiments, we further confirm that Er creates a level located 40 meV above the valence band. Density of this center increases in the material after high temperature annealing. We suggest that the Er-related level is due to Er atoms occupying cation sites in the material and acting as an isoelectronic impurity. © 1997 American Institute of Physics.

Journal of Applied Physics

Effect of Er dopant on the properties of In0.53Ga0.47As layers grown by liquid phase epitaxy

Deep level transient spectroscopy studies of GaAs:Sb layers, grown by liquid phase epitaxy reveal the existence of two electron traps with activation energies of 0.4 and 0.54 eV. High temperature annealing of the material reduced the density of the former trap while that of the latter is increased substantially. Density of the 0.54 eV trap is also found to be controlled by the Sb content in the material. These two results, together with the obtained signature of the 0.54 eV trap, suggest that it is the same as the Sb Ga related electron trap observed previously in GaAs:Sb materials grown by other techniques. Annealing increases the density of this trap by creating more SbGa defects as a consequence of Ga out-diffusion from the material. Photocapacitance measurements indicate the presence of a 0.75 eV electron trap in the annealed layers, which is identified with the second charge state of the SbGa electron trap. © 1995 American Institute of Physics.

Electron traps in GaAs:Sb grown by liquid phase epitaxy

Photocapacitance measurements in the photon energy range of 0.64 to 1.27 eV are done on GaAs layers grown by liquid phase epitaxy (LPE) and doped with varying amounts of indium (In) and antimony (Sb). Two hole traps with optical ionization energies of 0.65 and 0.79 eV are revealed in the material which are assumed to be two levels associated with the hole trap B reported in the literature. In addition, the hole trap A, usually found in LPE GaAs is also detected here by optical deep level transient spectroscopy (ODLTS) technique. The results of trap density measurements, as functions of isoelectronic doping concentration, indicate that VGa is an active constituent of the hole traps in LPE GaAs. The concentration of the 0.79 eV trap is found to be reduced in the material with high concentration of Sb. The analysis of photocapitance data using the existing theoretical models indicates the presence of an electron trap with activation energy of 0.75 eV in the heavily Sb‐doped material. This trap may be identified with the second charge state of the SbGa electron trap, obtained previously in bulk and metalorganic vapor phase epitaxial GaAs doped with Sb. The sharp reduction of the 0.79 eV hole trap density in Sb‐doped materials is explained by assuming the complex GaAsV Ga−, as its source. Copyright © 1994 WILEY‐VCH Verlag GmbH &amp; Co. KGaA

physica status solidi (b)

Dominant Traps in Liquid Phase Epitaxial GaAs Studied by Controlled Doping with Indium and Antimony

Results of Hall, photoluminescence and photocapacitance measurements performed on GaAs layers grown by liquid-phase epitaxy (LPE) and doped with various amounts of indium (In) and antimony (Sb) are presented. Hall measurements show that such doping marginally enhances the mobility in a certain optimum doping range. Near-band-edge photoluminescence spectra indicate the presence of CAs and SiAs as major acceptor impurities in lightly In-doped material. The latter impurity is not detected in heavily In-doped GaAs layers or in Sb-doped layers with either low and high doping density. Photocapacitance measurements reveal the presence of hole traps A and B, reported previously in undoped LPE GaAs. Indium doping reduces the total density of these traps. Furthermore, Sb doping induces a very sharp fall in the density of trap B. The results indicate that the hole trap B may be related to a GaAs antisite defect.

Journal	Bulletin of Materials Science
Publisher	Indian Academy of Sciences
ISSN	0250-4707
Open Access	Yes