We produce experimental 980 nm vertical cavity surface emitting lasers (VCSELs) with a wide range of oxide aperture diameters (ø) from ∼2.5 to 15 µm on wafers designed to minimize the epitaxial growth and VCSEL design complexity. The structures are grown in batches of 12, 3-inch diameter wafers in a production metal-organic vapor phase epitaxy machine. We characterize the top emitting VCSELs at room temperature (∼25 °C) – grouped into unit cells with 16 rows and 15 columns—using an automated (university-built) wafer mapping system, resulting in two-dimensional colorized maps of several performance attributes of interest including optical output power, threshold current, and maximum power conversion efficiency. By etching part of the topmost layer of the upper distributed Bragg reflector to decrease the VCSEL optical cavity photon lifetime, we boost the small signal modulation bandwidth (f_3dB). The room temperature maximum f_3dB is ∼30 GHz for VCSELs with ø ∼3 µm and ∼20 GHz for VCSELs with ø ∼15 µm.

Hot electron light emission and lasing in semiconductor heterostructure (Hellish) devices are surface emitters the operation of which is based on the longitudinal injection of electrons and holes in the active region. These devices can be designed to be used as vertical cavity surface emitting laser or, as in this study, as a vertical cavity semiconductor optical amplifier (VCSOA). This study investigates the prospects for a Hellish VCSOA based on GaInNAs/GaAs material for operation in the 1.3-μm wavelength range. Hellish VCSOAs have increased functionality, and use undoped distributed Bragg reflectors; and this coupled with direct injection into the active region is expected to yield improvements in the gain and bandwidth. The design of the Hellish VCSOA is based on the transfer matrix method and the optical field distribution within the structure, where the determination of the position of quantum wells is crucial. A full assessment of Hellish VCSOAs has been performed in a device with eleven layers of Ga_0.35In_0.65N_0.02As_0.08/GaAs quantum wells (QWs) in the active region. It was characterised through I-V, L-V and by spectral photoluminescence, electroluminescence and electro-photoluminescence as a function of temperature and applied bias. Cavity resonance and gain peak curves have been calculated at different temperatures. Good agreement between experimental and theoretical results has been obtained.

Plastics production is increased recently due to their various applications such as construction, electronic, packaging and others. The rising in plastics demand lead to developed of recycling and energy recovery method to control plastic wastes. Recycling process is needs to be arranged according to resins, colors and transparency of all plastics. Energy dispersive X-ray fluorescence (EDXRF) was developed for the determination of the chemical composition in different plastics materials (with resin identification code) of PETE (1) or PET (01), HDPE (2) or PE-HD (02), V (3) or PVC (03), LDPE (4) or PE-LD, PP (5) or PP (06), PS (6) or PS (06) and Others (7) or O (07). XRF was measured elements such as Si, S, Cl, Fr, Ca, Ti, V, Fe, Cu, Zn, As, Kr, Zr, Nb, Mo and Nb in both k _α and k _β lines, where PP with high percentage in both PET and PVC plastics, which is highly hazardous. In addition, chemical compositions in percentages were detected for various plastics materials.

The Top-Hat hot electron light emission and lasing in semiconductor heterostructure (HELLISH)-vertical cavity semiconductor optical amplifier (VCSOA) is a modified version of a HELLISH-VCSOA device. It has a shorter p-channel and longer n-channel. The device studied in this work consists of a simple GaAs p-i-n junction, containing 11 Ga0.35In0.65 N0.02As0.08/GaAs multiple quantum wells in its intrinsic region; the active region is enclosed between six pairs of GaAs/AlAs top distributed Bragg reflector (DBR) mirrors and 20.5 pairs of AlAs/GaAs bottom DBR mirrors. The operation of the device is based on longitudinal current transport parallel to the layers of the GaAs p-n junction. The device is characterised through I-V-L and by spectral photoluminescence, electroluminescence and electro-photoluminescence measurements. An amplification of about 25 dB is observed at applied voltages of around V = 88 V.

The hot electron light emitting and lasing in semiconductor heterostructure-vertical-cavity semiconductor optical amplifier (HELLISH-VCSOA) device is based on Ga0.35In0.65 N0.02As0.08/GaAs material for operation in the 1.3-μm window of the optical communications. The device has undoped distributed Bragg reflectors (DBRs). Therefore, problems such as those associated with refractive index contrast and current injection, which are common with doped DBRs in conventional VCSOAs, are avoided. The gain versus applied electric field curves are measured at different wavelengths using a tunable laser as the source signal. The highest gain is obtained for the 1.3-μm wavelength when an electric field in excess of 2 kV/cm is applied along the layers of the device.