摘要:

Hot electron light emitting and laser semiconductor heterostructure (HELLISH-1) is a novel surface emitting device. It utilizes longitudinal transport where electric fields heat up electrons and holes in their respective channels simultaneously. Hot electrons and holes are then captured by mainly tunnelling and thermionic emission in the quantum well where radiative recombination occurs. In this work, we demonstrate and compare the operation of HELLISH-1 and ultrabright HELLISH-1 (UB-HELLISH-1). The latter is an improved version of HELLISH-1 which incorporates a distributed Bragg reflector allowing detection of super radiant emission with a vastly improved full width at half-maximum. It is also shown that the emitted light intensity in the UB-HELLISH-1 device is enhanced by about two orders of magnitude compared with the simple structure. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118414

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Influence of postgrowth hydrogen treatments on nonradiative recombination centers in undoped and B-doped Si epilayers, grown by molecular beam epitaxy at low temperatures, are studied by optical detection of magnetic resonance. Hydrogen passivation of the dominant nonradiative defects in undoped Si is shown to be rather effective, whereas in the B-doped Si epilayers the effects of the hydrogen treatment of the same defects are found to be only marginal. Possible mechanisms for this are discussed. Information on two new nonradiative defects is provided. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118415

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

A method to form the gate oxide and recrystallize the polycrystalline silicon (poly-Si) active layer simultaneously is proposed. During the irradiation of excimer laser, the poly-Si film is recrystallized while the oxygen ion impurities injected into the amorphous silicon(a-Si) film are activated by laser energy and react with silicon atoms to formSiO2.Our experimental results show that a high quality oxide and a poly-Si film with fine grain have been fabricated successfully by the proposed method. High quality interface between oxide and poly-Si films has also been obtained. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118416

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Undamped photocurrent self-oscillations have been observed in a direct-gap GaAs-AlAs superlattices. The oscillations in the MHz regime appear over a wide voltage range, where the time-averaged I-V characteristic exhibits a strong negative differential conductivity. The frequency distribution is strongly dependent on the applied voltage and the laser intensity. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118417

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We have studied light-induced degradation in hydrogenated and deuterated amorphous silicon alloy solar cells. Replacing hydrogen with deuterium in the intrinsic layer of the cell improves stability against light exposure. Possible explanations for the improved stability are discussed. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118418

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

A two-terminal monolithic InGaP/GaAs tandem solar cell with a new efficiency record of 30.28&percent; is realized with a practical large area of 4 cm2under one-sun air-mass 1.5 global illumination. We report improvements of the tandem cell performance by introducing a double-hetero (hereafter DH) structure InGaP tunnel junction, in which the InGaP layers are surrounded by high band gap AlInP barriers. The DH structure by AlInP barriers increase the peak current of InGaP tunnel junction. The AlInP barrier directly below the InGaP top cell, which takes the part of a back surface field (hereafter BSF) layer, is found to be considerably effective in reflecting minority carriers in the top cell. The AlInP BSF layer does not only form a high potential barrier but also prevents the diffusion of zinc from a high doped tunnel junction toward the top cell during epitaxial growth. Furthermore, an InGaP tunnel junction reduces the absorption loss, which exists in a GaAs tunnel junction, and increases the photogenerated current in the GaAs bottom cell. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118419

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The vertical scaling of oxide thickness in the ultra large scale integrated era places stringent requirements on oxide quality. In this letter we report optimization studies in the growth of ultrathin oxynitrides in the sub 3 nm range. The oxynitride growth technique used involved self-limiting growth in nitric oxide (NO) followed by reoxidation in oxygen or nitrous oxide(N2O)ambient. This method allows tight control of oxide thickness and resulted in consistently low leakage currents over a range of thicknesses from 2 to 3 nm. The reliability of the oxynitrides is characterized usingQBD,stress-induced leakage and surface charge and contact potential difference measurements. Charge-to-breakdown(QBD)data indicate that the reliability of the oxide degrades with increasing nitridation times in an NO ambient. Increasing reoxidation times in O2have a similar effect. It is found that an improvement in reliability can be obtained by reoxidation in anN2Oambient. Surprisingly, reoxidizing inN2Oproceeds at a higher rate than in O2and this enables the use of lower thermal budgets. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118389

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We have observed visible light emission from Co-silicided junctions by emission microscopy. It was found that leakage current across the junction was accompanied by weak emission of light arising from spots distributed spatially on the electrode. In addition, the emission characteristics depended on the annealing temperature of the metallization process. It can be concluded that a plausible leakage origin is anomalous diffusion of Co, resulting in a locally high electric field. We also measured the energy dependence of the emission intensity and found that the emission intensity increases with decreasing photon energy. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118420

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We fabricate thin crystalline silicon solar cells with a minority carrier diffusion length of 0.6±0.2 &mgr;m by direct high-temperature chemical vapor deposition on glass substrates. This small diffusion length does not allow high cell efficiencies with conventional cell designs. We propose a new cell design that utilizes submicron thin silicon layers to compensate for low minority carrier diffusion lengths. According to theoretical modeling, our design exhibits excellent light trapping properties and allows for 10&percent; efficiency at an optimum cell thickness of 0.4&mgr;m only. This submicron range of cell thicknesses was formerly thought to require direct band gap semiconductors. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118421

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

By electron-beam lithography and wet chemical etching quantum boxes with a controlled shape as, e.g., a rectangular cross section, can be realized. We have fabricated quantum boxes with approximately constant widths of 50–60 nm and strongly varying lengths (150–80 nm). The luminescence of the structures shows a shift of the ground-state emission to higher energy as well as transitions between excited box states. By comparison with model calculations the changes of the emission spectra are related to the length quantization in the structures. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118384

出版商:AIP    

年代:1997

数据来源: AIP