Effects of crystallinity and point defects on optoelectronic applications of β-Ga2O3 epilayers

This study evaluates the effect of crystallinity and point defects on time-dependent photoresponsivity and the cathodoluminescence (CL) properties of β-Ga2O3 epilayers. A synchrotron high-resolution X-ray technique was used to understand the crystalline structure of samples. Rutherford backscattering spectroscopy was used to determine the net chemical composition of the samples to examine the type and ratio of their possible point defects. The results show that in functional time-dependent photoresponsivity of photodetectors based on β-Ga2O3 epilayers, point defects contribution overcomes the contribution of crystallinity. However, the crystalline structure affects the intensities and emission regions of CL spectra more than point defects

Healing of Surface States and Point Defects in Single-Crystalline β-Ga₂O₃ Epilayer

Abstract not Available.</jats:p

Healing of Surface States and Point Defects in Single-Crystalline β-Ga₂O₃ Epilayer

Single-crystalline β-Ga2O3 epilayer on (0001) sapphire was grown at low temperature and low pressure by MOCVD. The as-grown β-Ga2O3 epilayer was annealed at 800 ºC in atmosphere. Crystal structure and quality of the epilayer remained the same after annealing. Influence of surface states and point defects of β-Ga2O3 epilayers before and after annealing are studied using room-temperature Photoluminescence (PL) and I-V characteristics. The significant difference in PL property of β-Ga2O3 and big difference (~5 orders in magnitude) in dark current before and after annealing is attributed to the healing of the surface states and point defects. Gallium oxide is known for its high density of oxygen vacancies. Annealing single-crystalline β-Ga2O3 epilayer at high temperature makes the healing possible, probably due to oxygen adsorption. A significant healing of surface states and point defects in single-crystalline β-Ga2O3 indicates its high potential in fabrication of optoelectronic devices.</jats:p

P-Side up Thin Film AlGaInP-Based Light Emitting Diodes with Mesh Patterned Ohmic Contact

High-brightness p-side up AlGaInP-based red light emitting diodes (LEDs) with mesh patterned GaAs contact layers were fabricated. P-GaP was served as a current spreading and a window layer. P-GaP/AlGaInP/GaAs structures were epitaxially grown using metal organic chemical vapor deposition technique. Two-time-transferring technique lets p-GaP layer remain at the top side of each structure for better current spreading. Moreover, the GaAs contact layer had been further processed to mesh pattern structure and transferred to the rear-side of each device. Comparing two types of AlGaInP LEDs with and without mesh pattern shows a significant improvement in output power and luminous for mesh patterned GaAs devices.</jats:p

P-Side up Thin Film AlGaInP-Based Light Emitting Diodes with Mesh Patterned Ohmic Contact

Abstract not Available.</jats:p

Growth and Characterization of Single Crystalline Ga-doped ZnO Thin Films Using Metal-Organic Chemical Vapor Deposition

Abstract not Available.</jats:p

Growth and Characterization of Single Crystalline Ga-doped ZnO Thin Films Using Metal-Organic Chemical Vapor Deposition

Ga-doped ZnO (GZO) materials with high thermal stability and high carrier mobility are essential for the development of transparent conductive electrodes (TCE). We changed the amount of Ga doping into ZnO thin films to decrease the electric resistivity of ZnO thin film. The GZO films have been grown on c-plane sapphire substrate by metal-organic chemical vapor deposition (MOCVD). It was found that GZO films transparency rate can reach more than up 90 %, and up to 10-4 Ω-cm resistivity magnitude. The results show that GZO transparent conductive films were thermal annealing treatment under nitrogen ambient at for 2 minutes by rapid thermal annealing. And Ga doping into the ZnO is about to 1020 cm-3. It reveals that the GZO can significant improve the conductivity and increase the carrier concentration.</jats:p

Defects study of MOCVD grown β-Ga₂O₃films

Highly (-201) oriented ??-Ga2O3 films prepared by metal-organic chemical vapor deposition on (0001) sapphire substrates, undergone different post annealing temperatures to study their resistivity under harsh environment. Both of Rutherford backscattering spectrometry and cross-sectional transmission electron microscopy (TEM) results are exposing a harmony between oxygen vacancies and gallium interstitials. TEM characterization of samples determines a relationship between interstitials and formation of screw dislocations. Cathodoluminecsnece investigated under different applied voltages is found to be applicable to study chemistry of the bulk and surface of ??-Ga2O3. ? 2013 SPIE.EI