Jesuits arrived in the land of the New Kingdom of Grande (Colombia) at the beginning of the 17th century. They founded colleges in all most important towns and began the mis-sionary service among Indians, according to the scheme of so-called ‘doctrinas’, i.e. villages inhabited by autochthons. During the years 1605-1660 they worked in a few doctrines on Altiplano in the surroundings of Bogota and Tunja and on eastern slopes of the Andes. Their service was usually very effective and carried out according to the established methodology of the missionary work. They were appealing to the following rules: systematic and regular religious education, knowledge of the local languages by missionaries, development of the educational system including study of the singing and the music, practising solemn liturgy based on solid and well equipped churches. The past experience of the work in ‘doctrinas’ was used in the second half of the 17th century during the establishment of Jesuits’ reductions in Casanare, Meta and Orinoko.
The work presents doping characteristics and properties of high Si−doped InGaAs epilayers lattice−matched to InP grown by low pressure metal−organic vapour phase epitaxy. Silane and disilane were used as dopant sources. The main task of investigations was to obtain heavily doped InGaAs epilayers suitable for usage as plasmon−confinement layers in the construction of mid−infrared InAlAs/InGaAs/InP quantum−cascade lasers (QCLs). It requires the doping concentration of 1×1019 cm–3 and 1×1020 cm–3 for lasers working at 9 μm and 5 μm, respectively. The electron concentration increases linearly with the ratio of gas−phase molar fraction of the dopant to III group sources (IV/III). The highest electron concentrations suitable for InGaAs plasmon−contact layers of QCL was achieved only for disilane. We also observed a slight influence of the ratio of gas−phase molar fraction of V to III group sources (V/III) on the doping efficiency. Structural measurements using high−resolution X−ray diffraction revealed a distinct influence of the doping concentration on InGaAs composition what caused a lattice mismatch in the range of –240 ÷ –780 ppm for the samples doped by silane and disilane. It has to be taken into account during the growth of InGaAs contact layers to avoid internal stresses in QCL epitaxial structures.