Font Size: a A A

Interfacial Structure Of InGaAs/GaAsP Quantum Well And Performance Of Laser Device

Posted on:2017-01-02Degree:DoctorType:Dissertation
Country:ChinaCandidate:H L DongFull Text:PDF
GTID:1108330503457445Subject:Materials Science and Engineering
Abstract/Summary:PDF Full Text Request
Semiconductor laser has been a focus for a long time in the field of optoelectronic materials because of its small bulk, little weight, high power, high power conversion efficiency, long life etc. Photoelectric properties and applications of GaAs based laser have already made great progress. However, a number of hurdles still need to be overcome, such as the power efficiency droop phenomenon under high current injection, high loss, threshold current, electrical-to-optical conversion efficiency, carrier thermal escape, lower slope efficiency and so on. The research has found that the interfaces between the various functional layers in the laser device not only have the function of matter and energy transfer, but also play a crucial role in function implementation and improvement of device performance. In this thesis, the relationship between interface structure and photoelectric properties was studied in GaAs based laser device. On this basis, the photoelectric performance of laser device has been improved by designing and optimizing those interfacial structures. Based on the introduction of GaAs based laser light-emitting principle and structure characteristics, the main factors of well/barrier interfacial structures affecting photoelectric properties were analyzed, including interfacial structure of indium diffusion layer in InGaAs/GaAsP quantum well was effected by growth temperature, interfacial structure quality and carrier distribution in InGaAs/GaAsP quantum well was effected by different phosphorus composition in GaAsP layers, the transformation of interfacial structure in InGaAs/GaAsP quantum well was effected by different substrate misorientation. The contents and the obtained results are described as follows:1. In order to obtain better interfacial structure of InGaAs/GaAsP multiple quantum wells by regulating growth techniques, we systematical analyze the effect of growth temperature on multiple quantum well during the growth, which caused indium(In) interfacial diffusion problem because of environment of high temperature. In atomic diffusion length become longer because of high temperature, which could cause alloy disorder of wells/barrier interface layer increasing. Thus electron mobility decreases and alloy scattering increases. The growth temperature of multiple quantum wells was designed and regulated for 620 ℃, 650 ℃ and 680 ℃, separately. The results indicate the thinnest indium diffusion zone InGaAsP layer was obtained at 650 ℃ from the heterointerface between GaAsP layer and InGaAs. Meanwhile, the formation mechanism of InGaAsP layer was discussed, and the optoelectronic property of multiple quantum wells was analyzed.2. The effect of the height of potential barrier on the confined level of carrier transport was studied by adopting different phosphorus content in GaAsP barrier in order to improve internal quantum efficiency. Carrier distribution, binding capacity and optoelectronic property were affected by different P composition in barrier using k?p method in theory systematically. On the basis of theoretical design, multiple quantum well structures with different phosphorus composition were grown, and then the structure and optical properties of interface were analyzed by testing equipment. Finally, through the characterization of the performance of the photoelectric of laser device with different P composition in barrier, we obtained that the best photoelectric performance parameters of the laser device with 0.145 P in barrier. The internal quanntum efficiency could up to 98 % and the threshold current is about 0.3 A.3. We analyzed GaAs substrate with different miscut angle of 0°, 2° and 15° which has an influence on interfacial structure of InGaAs/GaAsP multiple quantum wells as active region in laser device. Under the condition of the same process parameters, we observed the unique surface morphologies of multiple quantum well structures on the GaAs substrates with different angles. From dependent-temperature photoluminescence, it was observed that the luminescence from the quantum wells grown on a vicinal surface exhibits a red-shift with respect to the 0° case. An extra emission was observed from the 2° and 15° off samples, indicating optic characteristics of quantum wire and pyramidal self-controlled quantum-dot systems, respectively. The formation mechanism of different surface morphologies was discussed. The relationship between In GaAs/GaAsP MQWs grown on vicinal substrates and their optical and structural properties was explained, which provides technological basis for obtaining different self-controlled nanostructure.
Keywords/Search Tags:InGaAs/GaAsP, interfacial structure, potential barrier, vicinal substrate, dependent-temperature photoluminescence
PDF Full Text Request
Related items