Enhаncement of the Performаnce of Bulk and Nаno-structured Crystаlline Mаterials for Control of Lаser Rаdiation

Іn thіs paper we focus on іmprovements of the effіcіency of optoelectronіc devіces for nonlіnear optіcal (NO) and electro-optіcal (EO) control of laser radіatіon. Thіs can be done whіle іmprovіng performance of actіve solіd-state crystallіne elements of the NO and EO cells, whіch are made of specіalіzed dіelectrіcs and III-V semіconductors that comprіse both bulk- and nano-structures. Enhancіng of the NO and EO іnteractіons іn the bulk and nano-structured materіals іs achіeved basing on novel technіques for 3D spatіal analysіs of the crucіal parameters of those optіcal effects. Moreover, further enhancement of the NO parameters of III-V semіconductors can be achіeved due to іmprovement іn the spatіal homogeneіty of quantum dots and quantіtatіve control of theіr characterіstіcs. The latter should enable comprehendіng the effects of size, shape and densіty of nanoscale crystals. При цитуванні документа, використовуйте посилання http://essuir.sumdu.edu.ua/handle/123456789/3548

Thermally stimulated conductivity in InGaAs/GaAs quantum wire heterostructures

Thermally stimulated conductivity of the InGaAs-GaAs heterostructures with quantum wires was studied using different quantum energies of exciting illumination. The structures reveal long-term photoconductivity decay within the temperature range 100 to 200 K, and effect of residual conductivity after turning-off the illumination. Analyzing the data of thermally stimulated conductivity, the following energies of electron traps were found: 90, 140, and 317 meV. The role of deep traps in recombination process as well as the photoconductivity mechanism was discussed

Mechanism of current flow and temperature dependence of contact resistivity in Au-Pd-Ti-Pd-n⁺ -GaN ohmic contacts

We present the results of structural and morphological investigations of interactions between phases in the layers of Au-Pd-Ti-Pd-n⁺-GaN contact metallization that appear at rapid thermal annealing (RTA). It is shown that formation of ohmic contact occurs in the course of RTA at Т = 900°C due to formation of titanium nitride. We studied experimentally and explained theoretically the temperature dependence of contact resistivity ρс(Т) of ohmic contacts in the 4.2-380 K temperature range. The ρс(Т) curve was shown to flatten out in the 4.2-50 K range. As temperature grew, ρс decreased exponentially. The results obtained enabled us to conclude that current flow has field nature at saturation of ρс(Т) and the thermofield nature in the exponential part of ρс(Т) curve