Subband electron properties of InGaAs/InAlAs high-electron-mobility transistors with different channel chickness

Magnetotransport properties of In-0.53 GaAs/In-0.52 AlAs high electron mobility transistor (HEMT) structures with different channel thickness of 10-35 nm have been investigated in magnetic fields up to 13 T at 1.4 K. Fast Fourier transform has been employed to obtain the subband density and mobility of the two-dimensional electron gas in these HEMT structures. We found that the thickness of channel does not significantly enhance the electron density of the two-dimensional electron gas, however, it has strong effect on the proportion of electrons inhabited in different subbands. When the size of channel is 20 nm, the number of electrons occupying the excited subband, which have higher mobility, reaches the maximum. The experimental values obtained in this work are useful for the design and optimization of InGaAs/InAlAs HEMT devices.

Optical analysis of dislocation-related physical processes in GaN-based epilayers

In this paper, recent progresses in optical analysis of dislocation-related physical properties in GaN-based epilayers are surveyed with a brief review. The influence of dislocations on both near-band edge emission and yellow luminescence (YL) is examined either in a statistical way as a function of dislocation density or focused on individual dislocation lines with a high spatial resolution. Threading dislocations may introduce non-radiative recombination centers and enhance YL, but their effects are affected by the structural and chemical environment. The minority carrier diffusion length may be dependent on either dislocation density or impurity doping as confirmed by the result of photovoltaic spectra. The in situ optical monitoring of the strain evolution process is employed during GaN heteroepitaxy using an AIN interlayer. A typical transition of strain from compression to tension is observed and its correlation with the reduction and inclination of threading dislocation lines is revealed. (c) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

1.3 mu m gain coupled DFB laser with InGaAlAs MQW grown on absorptive InGaAsP corrugation

An InGaA1As multiquantum well (MQW) has been successfully overgrown on the absorptive InGaAsP corrugation for fabricating the 1.3 mu m gain coupled distributed feedback (DFB) lasers. The absorptive InGaAsP corrugation was efficaciously preserved during the overgrowth of the InGaA1As MQW active region. The absorptive InGaAsP corrugation has a relatively high intensity around the PL peak wavelength in comparison with that of the InGaA1As MQW. The fabricated DFB laser exhibited a side mode suppression ratio of 40 dB together with a high single-mode yield of 90%.

Effect of heavy boron doping on the electrical characteristics of SiGeHBTs

A modified version of the Jain-Roulston (J-R) model is developed that takes into account the compensation effect of B to Ge in strained SiGe layers for the first time. Based on this new model, the distribution of the bandgap narrowing (BGN) between the conduction and valence bands is calculated. The influence of this distribution on the transport characteristics of abrupt SiGe heterojunction bipolar transistors (HBTs) has been further considered by using the tunnelling and thermionic emission mechanisms instead of the drift and diffusion mechanisms at the interfaces where discontinuities in energy levels appear. The results show that our modified J-R model better fits the experimental values, and the energy band structure has a strong influence on electrical characteristics.

Diffractive Grating Based Out-of-Plane Coupling between Silicon Nanowire and Optical Fiber

Submitted by 阎军 (yanj@red.semi.ac.cn) on 2010-06-04T07:55:26Z No. of bitstreams: 1 Diffractive Grating Based Out-of-Plane Coupling between Silicon Nanowire and Optical Fiber.pdf: 232805 bytes, checksum: 0bd17756b8a703bf8337dd25bbddaca3 (MD5)

Design and Simulation Analysis of Spot-Size Converter in Silicon-On-Insulator

Submitted by 阎军 (yanj@red.semi.ac.cn) on 2010-06-04T08:02:20Z No. of bitstreams: 1 Design and Simulation Analysis of Spot-Size Converter in Silicon-On-Insulator.pdf: 239163 bytes, checksum: 82db1386c266d0c07442a972348da08c (MD5)

High-Order Microring Filters on SOI Wafer

Submitted by 阎军 (yanj@red.semi.ac.cn) on 2010-06-04T08:05:17Z No. of bitstreams: 1 High-Order Microring Filters on SOI Wafer.pdf: 236326 bytes, checksum: dea85274da2a205a54b8a46049db9c94 (MD5)

High-Q and High-extinction-ratio Microdisk Add-drop Filter with Grating Couplers in Silicon-on-Insulator

Submitted by 阎军 (yanj@red.semi.ac.cn) on 2010-06-04T08:08:51Z No. of bitstreams: 1 High-Q and High-extinction-ratio Microdisk Add-drop Filter with Grating Couplers in Silicon-on-Insulator.pdf: 662474 bytes, checksum: dbdd3fba410c875bd74a6d4823930a44 (MD5)

InGaAsP/InP Bistability Triangle Microlasers

Submitted by 阎军 (yanj@red.semi.ac.cn) on 2010-06-04T08:12:07Z No. of bitstreams: 1 InGaAsP-InP Bistability Triangle Microlasers.pdf: 305729 bytes, checksum: 9bfb7f71e2d39dc99bcee91b9a48de3c (MD5)

Large-Signal Performance of 1.3 mu m InAs/GaAs quantum-dot lasers

Submitted by 阎军 (yanj@red.semi.ac.cn) on 2010-06-04T08:15:32Z No. of bitstreams: 1 Large-Signal Performance of 1.3 mu m InAs-GaAs quantum-dot lasers.pdf: 281494 bytes, checksum: 1ebcdfdc887e3a3b279e07b3f655167b (MD5)

Demonstration of high efficient tunable lasing with one photonic crystal W1 waveguide

Submitted by 阎军 (yanj@red.semi.ac.cn) on 2010-06-04T08:18:15Z No. of bitstreams: 1 Demonstration of high efficient tunable lasing with one photonic crystal W1 waveguide.pdf: 564778 bytes, checksum: 1eb1246461d4a3fcc99e870bda90f9b4 (MD5)