Synergistic morphology control and non-radiative defect passivation using a crown ether for efficient perovskite light-emitting devices

Promoted CsPbBr3 PeLED electroluminescent performance has been achieved using HM12C4 via ameliorating the film morphology and passivating defects.

Cathodoluminescence Study of SiO2/4H-SiC Structures Treated with High-Temperature Post-Oxidation Annealing

The radiative defect centers in thermally-grown SiO2/4H-SiC structures with high-temperature post-oxidation annealing (POA) in various ambient gas, i.e. Ar, H2, and NOx, were examined using cathodoluminescence (CL) measurement. It was found that radiative centers with an extremely high luminescent efficiency were remained at the SiO2/SiC interfaces after Ar-POA and FGA. Thus, these defect centers are very stable against high-temperature annealing and reducing ambient. In contrast, NOx-POA significantly reduced amounts of the radiative defects that might be related to channel mobility improvement in SiC-MOSFETs.

Microstructures and Photoluminescence of a-Si:H/a-SiNx Multilayers Annealed at Different Temperature

Series of a-Si:H/a-SiNx multilayers were prepared by very high frequency plasma enhanced chemical vapor deposition system. As-deposited samples were thermally annealed at the various temperatures. The effects of thermal annealing on the properties of luminescence were investigated. The photoluminescence intensity of the film annealed at 600 °C is found to be higher than that of the film without annealing. However, with further increasing the annealing temperature from 600 °C to 800 °C, the photoluminescence intensity of the film rapidly decreases. Fourier transform infrared spectroscopy and Raman-scattering spectroscopy were used to study the changes of the microstructures and bonding configurations. Based on the measurements of structural and bonding configurations, the improved photoluminescence intensity is attributed to the forming of radiative defect states caused by the effusion of hydrogen in the films.

Surface Engineering of CuIn0.75Ga0.25Se2 Thin Films

In this paper the effects of post-deposition annealing followed by hydrogen ionimplantation on the properties of CuIn0.75Ga0.25Se2 thin films have been investigated. The samples were grown by flash evaporation onto glass substrates heated at temperature between room temperature and 200°C. Selected samples were subsequently processed under several sets of conditions, including vacuum, selenium, inert (argon) and forming gas (a 9:1 mixture of N2:H2) followed by hydrogen ion-implantation. A high resolution near-infrared photoacoustic spectrometer of the gas-microphone type was used for room temperature analysis of non-radiative defect levels in the as-grown, annealed and hydrogen implanted thin films. The absorption coefficient has been derived from the PA spectra to determine the gap energy and to establish the activation energies for several defect-related energy levels. The changes observed in the PA spectra following annealing and ionimplantation has been directly correlated with the compositional and structural properties of the samples.

Acceptors in undoped gallium antimonide

ABSTRACTUndoped GaSb materials were studied by temperature dependent Hall (TDH) measurements and photoluminescence (PL). The TDH data reveals four acceptor levels (having ionization energies of 7meV, 32meV, 89meV and 123meV) in the as-grown undoped GaSb samples. The 32meV and the 89meV levels were attributed to the GaSb defect and the VGa-related defect. The GaSb defect was found to be the important acceptor responsible for the p-type nature of the present undoped GaSb samples because of its abundance and its low ionization energy. This defect was thermally stable after the 500°C annealing. Similar to the non-irradiated samples, the 777meV and the 800meV PL signals were also observed in the electron irradiated undoped GaSb samples. The decrease of the two peaks' intensities with respect to the electron irradiation dosage reveals the introduction of a non-radiative defect during the electron irradiation process, which competes with the transition responsible for the 777meV and the 800meV PL peaks.