Computational Study of Damage Profiles and Energy Loss of Gallium Ion in Germanium Substrate

Computational calculation of energy loss and study of damage profiles during ionic implantation by gallium ions on germanium had been carried out. The required energies for doping of gallium ion on germanium, in order to obtain maximum damage at 600 Å, were calculated using SRIM; Stopping and Range of Ions in Matter. The ions when implanted independently on germanium causes the production of germanium recoils, vacancy-interstitial pairs, and phonons during the collision process. For 130 keV gallium ion, the energy used for ionization, phonon production and vacancies creation are 37.713 keV (29.01% of incident energy), 90.006 keV (64.29% of incident energy) and 8.71 keV (6.7% of incident energy) respectively. The amount of target displacement, replacement collisions and vacancies were also evaluated. Doping of gallium ions on germanium also reveals that the energy loss due to nuclear stopping was greater than electronic stopping.

Фотолюминесценция центров окраски германий-вакансия в полученных химическим газофазным осаждением алмазных частицах

Hot Filament Chemical Vapor Deposition technique was used to synthesize diamond particles with germanium-vacancy color centers on a germanium substrate. The formation of color centers occurred during the growth of diamond particles due to the incorporation of germanium atoms formed as a result of a crystalline germanium wafer etching with atomic hydrogen. The conditions of Chemical Vapor Deposition process which affect the photoluminescence of color centers of germanium vacancy in diamond particles, are considered. The highest photoluminescence intensity of germanium-vacancy color centers was achieved for diamond particles obtained on a substrate at a surface temperature close to the melting temperature of germanium. The photoluminescence spectra of the diamond particles also showed lines presumably associated with the optical centers which contain tungsten.

Coordinate dependent diffusion analysis of phosphorus diffusion profiles in gallium doped germanium

We have analyzed phosphorus diffusion profiles in an In0.01Ga0.99As/In0.56Ga0.44P/Ge germanium structure during phosphorus co-diffusion with gallium for synthesis of the germanium subcell in multi-junction solar cells.. Phosphorus diffused from the In0.56Ga0.44P layer simultaneously with gallium diffusion into the heavily gallium doped germanium substrate thus determining the specific diffusion conditions. Most importantly, gallium and phosphorus co-diffusion produces two p–n junctions instead of one. The phosphorus diffusion profiles do not obey Fick’s laws. The phosphorus diffusion coefficient DP depth distribution in the specimen has been studied using two methods, i.e., the Sauer–Freise modification of the Boltzmann–Matano method and the coordinate dependent diffusion method. We show that allowance for the drift component in the coordinate dependent diffusion method provides a better DP agreement with literary data. Both methods suggest the DP tendency to grow at the heterostructure boundary and to decline closer to the main p–n junction. The DP growth near the surface p–n junction the field of which is directed toward the heterostructure boundary and its decline near the main p–n junction with an oppositely directed field, as well as the observed DP growth with the electron concentration, suggest that the negatively charged VGeP complexes diffuse in the heterostructure by analogy with one-component diffusion.

Design of an isotropic all-dielectric metasurface on a substrate

Сформулирована математическая постановка задачи об одноволновом безотражательном покрытии на основе метаповерхности. Построена область допустимых значений геометрических параметров структуры. Предложена штрафная функция, благодаря которой обеспечивается применимость физической модели, а искомый минимум становится единственным. В качестве примера рассмотрена задача о безотражательной метаповерхности из шариков PbTe, помещенных на германиевую подложку. Рассчитан спектр отражения такой структуры в диапазоне 8-12 мкм. Проведено сравнение со спектрами метаповерхности без подложки и только одной подложки. A mathematical statement of the problem of one-wavelength antireflective coating based on a metasurface is formulated. The constraints on geometric parameters of the structure are found. A penalty function is proposed to ensure the applicability of the physical model and to provide the uniqueness of the desired minimum. As an example, the problem of antireflective metasurface composed of PbTe spheres located on a germanium substrate is considered. The reflectance spectrum of such a structure is found in the range 8-12 micrometers and is compared with the spectrum of the metasurface without a substrate and with the spectrum of an uncovered substrate.

MULTILAYERS DIAMOND-LIKE CARBON FILM WITH GERMANIUM BUFFER LAYERS BY PULSED LASER DEPOSITION

Multilayer diamond-like carbon film with germanium buffer layers, which was composed of several thick DLC layers and thin germanium island “layers” and named as Ge-DLC film, was prepared on the germanium substrate by ultraviolet laser. The Ge-DLC film had almost same surface roughness as the pure DLC film. Hardness of the Ge-DLC film was above 48.1[Formula: see text]GPa, which was almost the same as that of pure DLC film. Meanwhile, compared to the pure DLC film, the critical load of Ge-DLC film on the germanium substrate increased from 81.6[Formula: see text]mN to 143.8[Formula: see text]mN. Moreover, Ge-DLC film on germanium substrates had no change after fastness tests. The results showed that Ge-DLC film not only kept high hardness but also had higher critical load than that of pure DLC film. Therefore, it could be used as practical protective films.