We present a systematic investigation of calculating quantum dots （QDs） energy levels using finite element method in the frame of eight-band k · p method. Numerical results including piezoelectricity, electron ...We present a systematic investigation of calculating quantum dots （QDs） energy levels using finite element method in the frame of eight-band k · p method. Numerical results including piezoelectricity, electron and hole levels, as well as wave functions are achieved. In the calculation of energy levels, we do observe spurious solutions （SSs） no matter Burt Foreman or symmetrized Hamiltonians are used. Different theories are used to analyse the SSs, we find that the ellipticity theory can give a better explanation for the origin of SSs and symmetrized Hamiltonian is easier to lead to SSs. The energy levels simulated with the two Hamiltonians are compared to each other after eliminating SSs, different Hamiltonians cause a larger difference on electron energy levels than that on hole energy levels and this difference decreases with the increase of QD size.展开更多
We investigate the band structure of a compressively strained In（Ga）As/In0.53Ga0.47As quantum well （QW） on an InP substrate using the eight-band k.p theory. Aiming at the emission wavelength around 2.33 μm, we di...We investigate the band structure of a compressively strained In（Ga）As/In0.53Ga0.47As quantum well （QW） on an InP substrate using the eight-band k.p theory. Aiming at the emission wavelength around 2.33 μm, we discuss the influences of temperature, strain and well width on the band structure and on the emission wavelength of the QW. The wavelength increases with the increase of temperature, strain and well width. Furthermore, we design an InAs /In0.53Ga0.47As QW with a well width of 4.1 nm emitting at 2.33 μm by optimizing the strain and the well width.展开更多
In this paper, we present an investigation of type-II ＇W＇ quantum wells for the InAs/Ga1-xInxSb/A1Sb family, where ＇W＇ denotes the conduction profile of the material. We focus our attention on using the eight-band...In this paper, we present an investigation of type-II ＇W＇ quantum wells for the InAs/Ga1-xInxSb/A1Sb family, where ＇W＇ denotes the conduction profile of the material. We focus our attention on using the eight-band k. p model to calculate the band structures within the framework of finite element method. For the sake of clarity, the simulation in this paper is simplified and based on only one period--A1Sb/InAs/Ga1-xInxSb/InAs/A1Sb. The obtained numerical results include the energy levels and wavefunctions of carriers. We discuss the variations of the electronic properties by changing several important parameters, such as the thickness of either InAs or Cal_xInxSb layer and the alloy composition in Ga1-xInxSb separately. In the last part, in order to compare the eight-band k·p model, we recalculate the conduction bands of the ＇W＇ structure using the one-band k·p model and then discuss the difference between the two results, showing that conduction bands are strongly coupled with valence bands in the narrow band gap structure. The in-plane energy dispersions, which illustrate the suppression of the Auger recombination process, are also obtained.展开更多
We report the fabrication of intermediate-band solar cells(IBSCs)based on quantum dots(QDs),which consists of a standard P-I-N structure with multilayer stacks of InAs/GaAs QDs in the I-layer.Compared with conventiona...We report the fabrication of intermediate-band solar cells(IBSCs)based on quantum dots(QDs),which consists of a standard P-I-N structure with multilayer stacks of InAs/GaAs QDs in the I-layer.Compared with conventional GaAs single-junction solar cells,the IBSCs based on InAs/GaAs QDs show a broader photo-response spectrum(>1330 nm),a higher short-circle current(about 53%increase)and a stronger radiation hardness.The results have important applications for realizing high efficiency solar cells with stronger radiation hardness.展开更多
We demonstrate a technique of temperature compensation for 1.3μm InAs/GaAs quantum-dot(QD)lasers by facet coating design.The key point of the technique is to make sure that the mirror loss of the lasers decreases as ...We demonstrate a technique of temperature compensation for 1.3μm InAs/GaAs quantum-dot(QD)lasers by facet coating design.The key point of the technique is to make sure that the mirror loss of the lasers decreases as the temperature rises.To realize this,we design a type of facet coating by shifting the central wavelength of the facet coating from 1310nm to 1480nm,whose reflectivity increases as the emission wavelength of the lasers red-shifts.Consequently,the laser with the new facet coating exhibits a characteristic temperature doubled in size and a more stable slope efficiency in the temperature range from 10℃to 70℃,compared with the traditional one with a temperature-independent mirror loss.展开更多
基金Project supported by the National High Technology Research and Development Program of China(Grant No.2006AA03Z401)'One-Hundred Talents Program' of the Chinese Academy of Sciences,and the National Natural Science Foundation of China (Grant No.60876033)
文摘We present a systematic investigation of calculating quantum dots （QDs） energy levels using finite element method in the frame of eight-band k · p method. Numerical results including piezoelectricity, electron and hole levels, as well as wave functions are achieved. In the calculation of energy levels, we do observe spurious solutions （SSs） no matter Burt Foreman or symmetrized Hamiltonians are used. Different theories are used to analyse the SSs, we find that the ellipticity theory can give a better explanation for the origin of SSs and symmetrized Hamiltonian is easier to lead to SSs. The energy levels simulated with the two Hamiltonians are compared to each other after eliminating SSs, different Hamiltonians cause a larger difference on electron energy levels than that on hole energy levels and this difference decreases with the increase of QD size.
基金Supported by the National High-Technology Research and Development Program of China under Grant No 2006AA03Z401, One-Hundred Talents Program of Chinese Academy of Sciences, and the National Natural Science Foundation of China under Grant No 60876033.
基金Supported by the National High-Technology Research and Development Program of China under Grant No 2006AA03Z401, One-Hundred Talents Program of Chinese Academy of Sciences, and the National Natural Science Foundation of China under Grant No 60876033.
文摘我们报导 1.3 m InAs/GaAs 量点(QD ) 的分子的横梁取向附生生长有高典型的温度 T0 的激光。激光的活跃区域由五层的 InAs QD 组成， p 类型调整做。有 4 m 和 1200 m 的洞长度的条纹宽度的设备在不同温度下面在搏动的政体被制作并且测试。它被发现那到象在从 10 的温度范围的 532K 一样 QD
基金Project supported by the '100 Talents Program' of Chinese Academy of Sciences,China
文摘We investigate the band structure of a compressively strained In（Ga）As/In0.53Ga0.47As quantum well （QW） on an InP substrate using the eight-band k.p theory. Aiming at the emission wavelength around 2.33 μm, we discuss the influences of temperature, strain and well width on the band structure and on the emission wavelength of the QW. The wavelength increases with the increase of temperature, strain and well width. Furthermore, we design an InAs /In0.53Ga0.47As QW with a well width of 4.1 nm emitting at 2.33 μm by optimizing the strain and the well width.
基金supported by the National Natural Science Foundation of China (Grant No. 60636030)
文摘In this paper, we present an investigation of type-II ＇W＇ quantum wells for the InAs/Ga1-xInxSb/A1Sb family, where ＇W＇ denotes the conduction profile of the material. We focus our attention on using the eight-band k. p model to calculate the band structures within the framework of finite element method. For the sake of clarity, the simulation in this paper is simplified and based on only one period--A1Sb/InAs/Ga1-xInxSb/InAs/A1Sb. The obtained numerical results include the energy levels and wavefunctions of carriers. We discuss the variations of the electronic properties by changing several important parameters, such as the thickness of either InAs or Cal_xInxSb layer and the alloy composition in Ga1-xInxSb separately. In the last part, in order to compare the eight-band k·p model, we recalculate the conduction bands of the ＇W＇ structure using the one-band k·p model and then discuss the difference between the two results, showing that conduction bands are strongly coupled with valence bands in the narrow band gap structure. The in-plane energy dispersions, which illustrate the suppression of the Auger recombination process, are also obtained.
基金Supported by the One-Hundred Talents Program of Chinese Academy of Sciences,and the National Science Foundation of China under Grant Nos 60876033,61076050 and 61021003.
文摘We report the fabrication of intermediate-band solar cells(IBSCs)based on quantum dots(QDs),which consists of a standard P-I-N structure with multilayer stacks of InAs/GaAs QDs in the I-layer.Compared with conventional GaAs single-junction solar cells,the IBSCs based on InAs/GaAs QDs show a broader photo-response spectrum(>1330 nm),a higher short-circle current(about 53%increase)and a stronger radiation hardness.The results have important applications for realizing high efficiency solar cells with stronger radiation hardness.
基金Supported by the One-Hundred Talents Program of Chinese Academy of Sciences and the National Natural Science Foundation of China under Grant Nos 60876033,61076050 and 61021003.
文摘We demonstrate a technique of temperature compensation for 1.3μm InAs/GaAs quantum-dot(QD)lasers by facet coating design.The key point of the technique is to make sure that the mirror loss of the lasers decreases as the temperature rises.To realize this,we design a type of facet coating by shifting the central wavelength of the facet coating from 1310nm to 1480nm,whose reflectivity increases as the emission wavelength of the lasers red-shifts.Consequently,the laser with the new facet coating exhibits a characteristic temperature doubled in size and a more stable slope efficiency in the temperature range from 10℃to 70℃,compared with the traditional one with a temperature-independent mirror loss.
