RESEARCH OF STRUCTURE AND ELEMENT COMPOSITION AFTER LASER RADIATION ON GAP EPITAXIAL DIODE STRUCTURES

摘要

The research of epitaxial layers reconstruction of heterostructure semiconductor surface layers has fundamental value for studying of boundary characteristics with different lattice parameters and an element composition. The influence of radiation of the laser on volt-ampere characteristics and the internal quantum yield of GaP:Zn,O heterostructure electro-photoluminescence is investigated by combination of probe methods as X-ray diffraction in standing wave mode (XSW), Auger electron spectroscopy (AES), low electron energy diffraction (LEED), low energy ion scattering (LEIS), and secondary ion mass spectroscopy (SMS). The diode structure had continuous ohmic contacts on the part of p- and n-conductivity zones. The laser processing was carried out from the crystal surface, which was perpendicular to the p-n transition plane. The optical influence on a photodiode structure active zone was made by scanning of a laser beam by a diameter ～ 60 μm with speed 4 cm.s~(-1) with on their photoluminescence surface. The laser worked in a pulse mode on frequency 10.2 kHz at duration of a pulse of radiation ～ 0.3 ms and density of power flow ～ 10~6 W.cm~(-2). The scanning was carried out for one pass with 10 μm step. The results of influence at supercritical power flow laser radiation (more than 10~7 W.cm~(-2)) the strong decrease of a quantum yield luminescence and the growth of leakage currents were observed. The laser on alumino-yttrium garnet radiated on length of λ = 1.06 μm wave (it corresponds to energy photon as 1.17 eV), which is twice less than width of the GaP forbidden zone with same diode structures were carried out with test short-term current by duration 12 hours at density of a current 11 A.cm~(-2) and effective temperature of p-n transition at 115 ℃. It is supposed that the powerful optical irradiation, exciting an impurity atom's electronic subsystem, promotes course quasi-chemical reactions. The reasons of the changes of the element composition and lattice structure in an active zone of LED doping by zinc and oxygen on base the data of the indicated above methods are discussed.