Structural Modifications in Amorphous Ge Produced by Ion Implantation

Raman spectroscopy was used to analyze structural modifications of monocrystalline Ge implanted with 3 × 1012 to 3 × 1016 cm-274Ge ions, at either room temperature (RT) or liquid nitrogen (LN) temperature. In all implanted samples, beyond the amorphiza

Thermoelectric Effect Spectroscopy of Deep Levels in Semi-Insulating GaN

The report of thermoelectric effect spectroscopy (TEES) applied on semi-insulating GaN was presented. The type of TEES setup, especially suitable for film-on-substrate samples, was devised. TEES enabled determination of sign of observed deep traps. Using TEES and thermally stimulated current spectroscopy measurements in combination with the simultaneous multiple peak analysis formalism all important trap parameters were determined. The shallowest identified electron and hole traps had activation energies Ec−0.09 eV and Ev+0.167 eV, respectively. Results indicate that both these traps, oppositely charged are present in the studied material in relatively high concentrations causing the electrical compensation and high resistivity

Direct ion beam synthesis of II-VI nanocrystals

Abstract We have studied the direct synthesis of nanoparticles formed by dual implantation of large and equal doses of Cd + S, Zn + Te, Cd + Te or Pb + Te ions into SiO 2 substrate. Grazing incidence small angle X-ray scattering (GI-SAXS), transmittance measurements and Raman spectroscopy were used to investigate implanted composites. The 2D GISAXS patterns suggest the synthesis of nanoparticles already during ion implantation, performed either at 300 or at 77 K, while annealing at higher T causes an increase of the fraction and the average size of synthesized nanoparticles. After high-T annealing both optical methods detected nanocrystals of compound semiconductors CdS, ZnTe or CdTe through the appearance of the respective first optical gaps, E g , in transmittance measurements and characteristic LO peaks in Raman spectra. It is proposed that at high ion doses a fraction of implanted atoms synthesize already during implantation into amorphous aggregates of compound semiconductor, which transform into crystalline nanoparticles after annealing

Role of Contacts in Characterization of Deep Traps in Semi-insulating GaAs by Thermally Stimulated Current Spectroscopy

The role of contacts in characterization of traps in semi-insulating (SI) GaAs by thermally stimulated current (TSC) methods has been demonstrated by comparing alloyed In and soldered In contacts. Alloyed In contacts, which have an ohmic characteristic, assure high sensitivities in both TSC and temperature dependent photocurrent (PC), and both are important for determining the trap concentrations in SI GaAs. On the other hand, soldered In contacts, which act like Schottky barriers, cause a significant reduction of both PC and TSC, particularly at low temperatures, and can lead to a misinterpretation of TSC results

Role of Contacts in Characterization of Deep Traps in Semi-insulating GaAs by Thermally Stimulated Current Spectroscopy

The role of contacts in characterization of traps in semi-insulating (SI) GaAs by thermally stimulated current (TSC) methods has been demonstrated by comparing alloyed In and soldered In contacts. Alloyed In contacts, which have an ohmic characteristic, assure high sensitivities in both TSC and temperature dependent photocurrent (PC), and both are important for determining the trap concentrations in SI GaAs. On the other hand, soldered In contacts, which act like Schottky barriers, cause a significant reduction of both PC and TSC, particularly at low temperatures, and can lead to a misinterpretation of TSC results

GISAXS Studies of Structural Modifications in Ion-beam Amorphized Ge

Grazing incidence small angle scattering of X-rays (GISAXS) was used to analyze structural modifications in implantation-damaged Ge. Samples were implanted by different doses of 74Ge, from 3 × 1012 cm-2 to 3 × 1016 cm-2; at room- or liquid nitrogen-tem