Growth of CuInSe2 by metallorganic chemical vapour deposition (MOCVD): new copper precursor

Metallorganic chemical vapour deposition (MOCVD) of Cu-In-Se ternary compounds is performed in a horizontal reactor at atmospheric pressure. A copper precursor has been specially developed for this purpose and is used around room temperature. It is hexafluoroacetylacetonato copper mixed with trimethylamine (Cu(hfa)₂, NMe₃). The other source materials are triethylindium (TEIn), trimethylindium (TMIn) and hydrogen selenide (H₂Se). Experimental parameters are detailed and related to the film composition. Properties of thin films are also investigated in the whole range of compositions obtained.     

MOVPE grown Ga/sub 0.6/In/sub 0.4/Sb photodiodes for 2.55 mu m detection

Photodiodes with a long-wavelength cutoff extending out of 2.9 mu m have been fabricated from MOVPE-grown Ga/sub 0.6/In/sub 0.4/Sb homojunctions. These mesa devices without any passivation or antireflecting coating exhibit a peak efficiency as high as 43% at 2.60 mu m.<>     

Étude de la cinétique de croissance de couches ZnSe ET ZnS épitaxiées sur fluorine par transport en phase vapeur

Epitaxial layers of ZnSe and ZnS were grown on (111) calcium fluoride (CaF₂) substrates in an open tube system by reaction of hydrogen with the compounds in powdered form. Typical growth rates of 1–2 μm h^?1 for ZnSe and 3–5 μm h^?1 for ZnS have been obtained. The parameters investigated were source temperature, substrate temperature and hydrogen flow rate.The experimental results were compared with theoretical growth rates calculated from the partial pressures of the components. In this case, the growth rate is proportional to the concentration difference between the source and the substrate and contains one adjustable parameter which depends on the substrate temperature and vapour phase composition.     

Solution growth of n-type GaxIn1−xSb crystals and application to gunn effect

n type Ga_xIn_1?xSb crystals with 0 ? x ? 0.45 have been elaborated by mean of a solution growth method (T.G.Z.M.) using Indium as solvent and Indium antimonide as seed. The growth processus and resulting homogeneous material elaboration are described with the aid of the ternary phase diagram of the GaInSb system. Ga_xIn_1?xSb Gunn diodes were prepared. Current instabilities were obtained on some samples. The conditions for the Gunn effect observation in the alloy are given.     

Evaporation chimique du GaAs sous flux d'hydrogene et d'acide chlorhydrique

Studies of the etching behavior of GaAs with HCl as a function of temperature and etchant concentration indicate that temperature is the most significant parameter affecting the smoothness of the “B” face of the III-V compound. Similars results has been obtained with H₂ as etching gas only. Etching rates in mg.min^?1 and in microns.min^?1 are drawn.     

Etude de la segregation d'impuretes telles que Se et Te dans l'antimoniure de gallium

We have study the segregation coefficient k of selenium in gallium antimonide for slightly and heavily doped single crystals. We show that k is a function only of the growing rate. We compare there results to tellurium ones. We deduce the value of k when v is zero: this value is k_o = 0,013. We show also that the variation of the number of free carriers is linear with N_d the number of donors, in n type as well as p type.     

Contribution a l'etude du diagramme de phase du systeme CuxS (1.75⩽x⩽2) entre 10°C et 200°C

The published results 11 to 61 concerning CuS phase diagram in the range Cu_1.75S ? Cu₂S between 10°C and 200°C show the existence of many regions in which the results differ according to authors. We have study by differential thermal analysis and diffractometry X, the existence and the stability of the tetragonal phase 11, 21, anilite 151, and the Cu_1.89S compounds 141.     

Photoluminescence de ZnSe: Ga et ZnSe: As

The photoluminescence emission spectra of crystals of zinc selenide doped with Ga and As have been measured at 4.2°K. The effect of heat treating ZnSe in presence of Zn is investigated too. The more prominent features of the spectra are generally grouped as the so-called I₁ line, the I₂ line and the edge emission. The I₁ line is believed to be associated with an exciton bound to neutral donors. There are a number of divergent explanation of the edge emission.     

Growth and characterization of undoped and N-type (Te) doped MOVPE grown gallium antimonide

The growth of GaSb by MOVPE and itsn-type doping using a dimethyltellurium dopant source are investigated. The results of growth rate, morphology and Te incorporation as a function of growth parameters are given. Increasing growth temperature and V/III reactant ratio were found to reduce the Te incorporation. The lowest Hall carrier concentrations obtained at room-temperature, onp-type andn-type MOVPE GaSb are respectively:p _H= 2.2 × 10¹⁶cm⁻³ with a Hall mobility ofμ _H= 860 cm²/V.s andn _H= 8.5 × 10¹⁵cm⁻³ withμ _H= 3860 cm²/V.s. Furthermore, Hall mobilities as high as 5000 cm²/V.s were measured onn-type GaSb samples.     

The optical properties of sprayed CdS thin films

In the study presented in this paper we attempted to interpret the reflectance and the transmittance of sprayed CdS films. Assuming a model based on multilayer film theory we showed that sprayed CdS film is a combination of multilayer stacks of crystallites and gaseous inclusions.