The ultraviolet AlGaInN light-emitting diode under study is grown on a c-face sapphire substrate by low-pressure horizontal-flow metalorganic chemical vapor deposition (MOCVD). With increasing input current from 10 to 100 mA, the main peak of the emission wavelength shifts from 368 to 372 nm. The room-temperature output power is 0.8 mW at 20 mA. Under continuous-wave operation, an output power of 4 mW is achieved at a driving current of 125 mA. The simulation program, advanced physical model of semiconductor devices (APSYS), is used to fit in our experimental results in order to obtain an optimized structure. The device performance affected by piezoelectric and thermal effects is studied via drift-diffusion model for carrier transport, optical gain and loss. The optical performance of the ultraviolet light-emitting diodes with different numbers of quantum wells at various temperatures is numerically investigated. Preliminary simulated results indicate that when the number of quantum wells is 5 to 7, better output performance is obtained. To raise the internal efficiency and radiative recombination rate, a current blocking layer SiO<sub>2</sub> is used to guide and confine current flows through active region.
1.27 μm InGaAs:Sb-GaAs-GaAsP vertical cavity surface emitting lasers (VCSELs) were grown by metalorganic chemical vapor deposition (MOCVD) and exhibited excellent performance and temperature stability. The threshold current changes from 1.8 to 1.1 mA and the slope efficiency falls less than ~35% as the temperature raised from room temperature to 70oC. With a bias current of only 5mA, the 3dB modulation frequency response was measured to be 8.36 GHz, which is appropriate for 10 Gb/s operation. The maximal bandwidth is measured to be 10.7 GHz with modulation current efficiency factor (MCEF) of ~ 5.25 GHz/(mA)1/2. These VCSELs also demonstrate high-speed modulation up to 10 Gb/s from 25°C to 70°C.
In this article, the laser performance of the 1300-nm In<sub>0.4</sub>Ga<sub>0.6</sub>As<sub>0.986</sub>N<sub>0.014</sub>/GaAs<sub>1-x</sub>N<sub>x</sub> quantum well lasers with various GaAs<sub>1-x</sub>N<sub>x</sub> strain compensated barriers (x=0%, 0.5%, 1%, and 2%) have been numerically investigated with a laser technology integrated simulation program. The simulation results suggest that with x=0% and 0.5% can have better optical gain properties and high characteristic temperature coefficient T0 values of 110 K and 94 K at the temperature range of 300-370 K. As the nitrogen composition in GaAs1-xNx barrier increases more than 1% the laser performance degrades rapidly and the T0 value decreases to 87 K at temperature range of 300-340 K. This can be attributed to the decrease of conduction band carrier confinement potential between In<sub>0.4</sub>Ga<sub>0.6</sub>As<sub>0.986</sub>N<sub>0.014</sub> QW and GaAs<sub>1-x</sub>N<sub>x</sub> barrier and the increase of electronic leakage current. Finally, the temperature dependent electronic leakage current in the InGaAsN/GaAs<sub>1-x</sub>N<sub>x</sub> quantum-well lasers are also investigated.