Dimethylaminopropyl-dimethyl-indium (DADI) was used to grow GaInAs and GaInP in combination with two Ga precursors: dimethylaminopropyl-diethyl-gallium (DADEG) and the adduct TMGa-NH/sup i/Pr2. No side reactions with the hydrides could be detected. It is shown that the quality of the layers suffered from the instability of the evaporation rate of DADEG and from some gas-phase reactions between DADI and the Ga-adduct at atmospheric pressure near the substrate surface, although the evaporation rate of DADI is stable over time, as monitored by the composition reproducibility of ternary layers. Due to its lower chemical reactivity DADI can be easily synthesized in high purity, as demonstrated by Hall and photoluminescence (PL) experiments on the layers grown with DADI batches not specially purified.<>

The two novel liquid In precursors TMIn-HNiPr2 and (3-dimethylaminopropyl)dimethylindium (DADI) were synthesized and their behaviour in the MOVPE growth of InP studied. Layers with low temperature mobilities in excess of 100,000 cm2/V·s could be grown. When growing GaInAs, some side reactions between TMIn-HNiPr2 and AsH3 were observed, which did not significantly affect the layer quality. DADI could be used in combination with tertiarybutylphosphine resulting in acceptable InP quality at moderate growth temperatures.

The excitation and decay mechanisms of the Yb3+ intra-4f-shell emission are studied in n-type MOVPE-grown and p-type LPE grown InP:Yb layers by photoconductivity measurements, time-resolved photoluminescence, photoluminescence excitation and emission spectroscopy. Assuming a pseudo-donor or pseudo-acceptor-like character of the isoelectronic Yb3+ Td centre the temperature dependences of the 4f-shell transition intensity and lifetime can be consistently explained. Models for the excitation and decay processes of the Yb3+ photoluminescence are proposed.

InP doping superlattices (DSLs) were grown by atmospheric pressure metalorganic vapor phase epitaxy (MOVPE) and their stability was examined by annealing at high temperatures. Diethylzinc (DEZ) and H2S were used asp- andn-type doping sources, respectively. Photoluminescence (PL) measurements performed on as grown layers show a shift of the main emission peak with increasing excitation power in very good agreement with theoretical models. A comparison of the PL results between these structures and the annealed samples show that even at very high temperatures (up to 850° C) the tunability of the effective bandgap of the annealed superlattices is possible, although less pronounced than for the as grown layers. This is due to diffusion of the dopants, into adjacent layers and partial compensation of each other. Secondary ion mass spectrometry (SIMS) done on the as grown and annealed samples shows that only the Zn atoms diffuse. Diffusion coefficients obtained from the SIMS profiles give values in the range 1 × 10−14 <D < 9 × 10−14 cm2/s, still smaller than other published values estimated on layers, which did not suffer any treatment. This shows the high quality and stability of our layers even at high temperatures.

Doping experiments with zinc (Zn) in metalorganic vapor phase epitaxial (MOVPE) indium phosphide (InP) layers have been performed in the carrier concentration range 1 × 1017 < p < 2 × 1018 cm-3, using both DMZ and DEZ as p-doping sources. 0 The results of this study show that: (a) no memory effect and no diffusion of the Zn atoms into the substrate are detectable up to Zn concentrations of 2 × 1018 cm-3 (this is the saturation value of the active Zn atoms in InP); (b) diffusion is very strong at higher tot al Zn concentrations, because of Zn incorporation at interstitial sites. These results have been confirmed by growing doping superlattices with periods as short as 10 nm with doping concentrations of 1 × 1018 cm-3 and abrupt doping profiles as proven by secondary ion mass spectrometry (SIMS).

A new class of non-pyrophoric and almost air-resistant organometallic compounds of indium, aluminium and gallium has been synthesized for more convenient and safer application in vapour phase epitaxy of III–V semiconductor layers (metal-organic chemical vapour deposition (MOCVD)). It is represented by molecules which are intramolecularly and coordinatively saturated. By simple structure variations such physical properties as the melting point, boiling point and vapour pressure can be easily varied. Thus compounds are available, which are liquid at room temperature and have a vapour pressure which is high enough for MOCVD without additional heating of the source. Synthesis and initial epitaxy results are discussed.

Dimethyl (3-dimethylaminopropyl) indium was synthesized and used for the first time as an indium source for the growth of InP layers by metalorganic vapor phase epitaxy at atmospheric pressure. This compound is liquid at room temperature with a vapor pressure of 30–40 Pa at 30 °C, which enables its use at low source temperatures. The layers were grown at a bubbler temperature of 30 °C. The growth temperature was varied between 580 and 660 °C. Hall measurements revealed good electrical data with carrier mobilities up to 49 900 cm2 /V s at 77 K. Temperature-dependent photoluminescence experiments confirmed these results and indicated that zinc was the main residual acceptor impurity.

This paper presents proposals for the synthesis of several group III metal organics (In, Ga, Al compounds) and preliminary results on their use in the MOVPE (metal organic vapor phase epitaxy) of III-V semiconductors. The common feature of all these precursors is that they are saturated by interor intramolecular coordination. They are even non-pyrophoric and air resistant which is an interesting aspect with respect to safe handling. In addition, the compounds are liquid at room temperature with a low but sufficient vapor pressure for MOVPE without additional heating of the source.

Highly doped InP:Yb layers have been grown by adduct metalorganic vapor phase epitaxy at atmospheric pressure. Yb(MeCp)3, where Me=CH3 and Cp=n5-C5H5, was synthesized as Yb source material because of its relatively high vapor pressure at acceptable source temperatures. The layers were grown in a wide range of growth temperatures (560–670 °C) and Yb mole fractions (10−9–10−7). In photoluminescence experiments they showed strong Yb3+-4f emission. The layers were further characterized by Hall measurements and secondary-ion mass spectroscopy. In order to obtain n-type InP:Yb samples with high carrier concentrations we have grown InP layers double doped with S and Yb.