The present disclosure relates to a semiconductor light emitting device, comprising: a plurality of semiconductor layers, including a first semiconductor layer having a first conductivity, a second semiconductor layer having a second conductivity different from the first conductivity, and an active layer interposed between the first semiconductor layer and the second semiconductor layer, generating light via electron-hole recombination; a first electrode, supplying either electrons or holes to the plurality of semiconductor layers; a second electrode, supplying, to the plurality of semiconductor layers, electrons if the holes are supplied by the first electrode, or holes if the electrons are supplied by the first electrode; a non-conductive distributed bragg reflector coupled to the plurality of semiconductor layers, reflecting the light from the active layer; and a first light-transmitting film coupled to the distributed bragg reflector from a side opposite to the plurality of semiconductor layers with respect to the non-conductive distributed bragg reflector, with the first light-transmitting film having a refractive index lower than an effective refractive index of the distributed bragg reflector.

Semiconductor Light Emitting Device

Injection locking of AlGaAs double-heterostructure (DH) lasers was studied with respect to locking bandwidth, required power, and coherence. The relation of the locking bandwidth versus the ratio of locked laser power to injected power was consistent with the classical analysis on injection locking phenomena reported by Adler [2]. The measured maximum locking bandwidth was 5.8 GHz when the locking gain was 18 dB. A maximum gain of 40 dB was observed with a 500 MHz locking bandwidth. The power increase in the injected mode agrees well with theoretical values calculated with the van der Pol equation. The interference pattern was observed between an injecting beam and a locked laser beam. Visibility was the same as that obtained by the interference between forward and backward emitted beams in an identical free-running laser. Spurious mode suppression was observed when a single-frequency optical power is injected into an RF-modulated laser. Single longitudinal mode operation was obtained at a sufficiently high injecting level.

Injection locking in AlGaAs semiconductor laser

Refractive indices and absorption coefficients of In1−x Gax P1−yAsy for y = 0 to 1 lattice matched to InP and of GaAs and GaP have been measured by ellipsometry in the wavelength range between 365 and 1100 nm. The high‐purity layers (7×1014<n<2×1016 cm−3) used here were grown by liquid phase epitaxy. The quaternary refractive indices were also calculated from the measured indices of the constituent binary compounds by averaging the quantity (e−1)/(e+2). The e values were all taken at the same energy separation from the respective band gaps. The results of this new averaging procedure are compared with the measured indices and with the refractive index steps to InP deduced from lasers. In addition, the absorption coefficient of InP near the band gap was measured as a function of the doping level. Finally, the temporal growth of the natural oxide layer thickness dox on various InP and GaAs samples was determined by ellipsometry. For InP, the increase of dox is 0.39 nm per decade of time.

Optical properties of In1−xGaxP1−yAsy, InP, GaAs, and GaP determined by ellipsometry

A new high-performance 1.3-μm InGaAsP semiconductor laser is described, in which effective current confinement into the active region has been realized. A p-n-p-n current blocking structure is made by liquid-phase epitaxy (LPE) on both sides of the active-stripe mesa which is defined by a pair of channels in the double-heterostructure wafer. The double-channel-planar-buried-heterostructure laser diodes (DC-PBH LD's) exhibit high-laser performances, such as a high differential quantum efficiency of 78-percent maximum, which results in high electrical to optical power conversion efficiency 43 percent, and high light output power of over 50 mW, as a result of the improvement in the current blocking structure. The threshold current temperature sensitivity is found experimentally to be reduced remarkably by increasing the doping concentration in the p-cladding layer. Characteristic temperature as high as 100 K has been obtained. CW operation is possible up to 130°C.

InGaAsP double-channel- planar-buried-heterostructure laser diode (DC-PBH LD) with effective current confinement

Modern microelectronic device manufacture requires single-crystal silicon substrates of unprecedented uniformity and purity, As the device feature lengths shrink into the realm of the nanoscale, it is becoming unlikely that the traditional technique of empirical process design and optimization in both crystal growth and wafer processing will suffice for meeting the dynamically evolving specifications. These circumstances are creating more demand for a derailed understanding of the physical mechanisms that dictate the evolution of crystalline silicon microstructure and associated electronic properties. This article describes modeling efforts based on the dynamics of native point defects in silicon during crystal growth, which are aimed at developing comprehensive and robust tools for predicting microdefect distribution as a function of operating conditions. These tools are not developed independently of experimental characterization but rather are designed to take advantage of the very detailed information database available for silicon generated by decades of industrial attention. The bulk of the article is focused on two specific microdefect structures observed in Czochralski crystalline silicon, the oxidation-induced stacking fault ring (OSF-ring) and octahedral voids; the latter is a current limitation on the quality of commercial CZ silicon crystals and the subject of intense research. (C) 2000 Published by Elsevier Science S.A.

Defect engineering of Czochralski single-crystal silicon

Shunt current flowing through p-n-p-n current blocking layers is examined as a possible cause of excess temperature sensitivity of Ith and -ex which is often observed in InGaAsP BC and BH lasers. Under certain conditions, the shunt current reduces the T0 value of Ith from 65 K to 45 K and that of -ex from 130 K to 40 K.

Shunt current and excess temperature sensitivity of Ith and ηex in 1.3 μm InGaAsP DH lasers

The temperature dependence of the internal loss α of the InGaAsP/InP buired crescent (λ=1.3 µm) laser is presented in the temperature range 20~80°C. α is about 18 cm-1 and no apparent temperature dependence of α is observed in this temperature range. This indicates that the temperature-sensitive behavior of the threshold current in 1.3 µm laser is not due to the internal loss. The decrease in the external quantum efficiency with increasing temperature is attributed to the decrease in the internal quantum efficiency, which is possibly caused by some leakage current.

Internal Loss of InGaAsP/InP Buried Crescent (λ=1.3 µm) Laser

A 1.3 μm InGaAsP/InP buried crescent laser diode has been fabricated on p-InP substrate. The laser diode has a low threshold current, as low as 10 mA. It operates at the output power of 5 mW under CW condition at temperatures higher nary aging test at 70°C with a constant light output of 5 mW, the lasers have been operating stably for more than 1000 h.

High temperature CW operation of p-substrate buried crescent laser diode emitting at 1.3 μm

The temperature dependence of the internal loss α of the InGaAsP/InP buried crescent laser is presented in the temperature range 20–80 °C. α is about 18 cm−1, and no apparent temperature dependence of α is observed in this temperature range. This indicates that the temperature‐sensitive behavior of the threshold current in InGaAsP/InP long‐wavelength lasers is not due to the temperature dependence of internal loss. The decrease in the external quantum efficiency with increasing temperature is attributed to the decrease in the internal quantum efficiency.

Internal loss of InGaAsP/InP buried crescent (λ = 1.3 μm) laser

It is found that electroluminescent mode aging at high-temperature and high-current levels is useful for selecting long-lived InGaAsP 1.3 μm lasers. Lasers selected by this screening have little change in threshold current or forward voltage through the aging test at an elevated temperature with constant light-output power.

E. Oomura

Papers

Shunt current and excess temperature sensitivity of Ith and ηex in 1.3 μm InGaAsP DH lasers

Internal Loss of InGaAsP/InP Buried Crescent (λ=1.3 µm) Laser

High temperature CW operation of p-substrate buried crescent laser diode emitting at 1.3 μm

Internal loss of InGaAsP/InP buried crescent (λ = 1.3 μm) laser

Screening of long-wavelength laser at high temperature and high current levels