摘要:

This paper describes the application of a new iterative method to numerical calculation of the performance of amorphous siliconp‐i‐nsolar cells. Using this method, the effects of gap‐state density, dopant impurities (B and P), and various cell parameters (diffusion length, interface recombination velocities, thickness of theilayer, etc.) on cell characteristics are investigated. The calculated results show that a strong electric field advantageously effects cell characteristics (especially through fill factor) in thei‐layer where many photocarriers are generated. However, a uniform field isn’t always adequate for high conversion efficiency. The improvement in conversion efficiency provided by boron doping is attributed to stretching of the diffusion length rather than rearrangement of the field distribution.

ISSN:0021-8979    

DOI:10.1063/1.335958

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

We present an experimental and theoretical study ofn‐type Hg1−xCdxTe photoconductors in which a large band‐gap alloy was grown on top of a smaller band‐gap active region and contacts were made to the larger gap material. The larger band‐gap material causes an energy barrier to holes which decreases the rate at which they reach the high recombination region of the metal‐semiconductor interface. As a result, this heterojunction contact greatly reduces the effects of carrier sweepout on device performance and leads to much higher detector responsivities. Experimental results in a symmetric device with a cutoff wavelength of 7.8 &mgr;m at 77 K show responsivities in excess of 106V/W and detectivities close to the background limited value and nonsaturation of responsivity with bias voltage. In an asymmetric device, in which only one heterojunction contact was used, an order of magnitude increase in responsivity was observed when the heterojunction contact was biased to attract minority carriers, compared with the opposite bias polarity. A theoretical model of the heterojunction contact photoconductor is presented. Calculated results are in good agreement with experimental results. The results of the calculation suggest that the optimum compositional difference &Dgr;xof the two layers should be &Dgr;x∼0.04, and that the thickness of the large band‐gap region should be 2–3 &mgr;m.

ISSN:0021-8979    

DOI:10.1063/1.335959

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

This paper presents an overview of the status of a Josephson cache chip design at IBM in the Fall of 1983. Details of the design, organized as 1 K×4 bits, and employing a 2.5‐&mgr;m niobium edge‐junction technology, are found in the subsequent two adjoining papers. This paper presents, in a broader perspective than the adjoining papers, the background, motivation, changes from previous designs, and general difficulties of the design. General considerations related to the fabrication process and design methodology and an overview of components and the system environment are presented. A Pb‐predecessor design is used as a point of reference; the discussions emphasize changes to that work. Finally, inherent design difficulties and remaining uncertainties are discussed.

ISSN:0021-8979    

DOI:10.1063/1.335960

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

A detailed optimized design of a 1 K‐bit memory cell array with drivers and reset gates has been carried out based upon a set of projections for achievable tolerances in linewidths, resistances, and Josephson critical currents in a 2.5‐&mgr;m technology employing niobium edge junctions. The cell operating regions were significantly widened relative to a predecessor Pb‐alloy design by adjusting gate and cell inductances, adjusting current levels, and by employing a different timing sequence for application of write controls. Much‐improved control of array‐line current oscillations, without loss of speed, was achieved by employing a distributed filtering scheme using distributed damping. The design employs trimming of currents to accommodate ±8% chip‐to‐chip differences in the average critical current. The cell size is 63×63 &mgr;m. Monte Carlo calculations of threshold curve tolerances and operating current sensitivities and tolerances lead to a design‐limited yield of about 95% for 4 K bits.

ISSN:0021-8979    

DOI:10.1063/1.335961

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

Designs for peripheral and timing circuits for a Josephson cache memory chip, organized as 1 K × 4‐bits, are described. The designs were carried out employing a 2.5‐&mgr;m minimum‐linewidth niobium edge‐junction technology, in conjunction with the memory cell and driver array design described in the preceding companion paper. Significant changes in decoding, sensing, and timing, relating to widening operating margins over a predecessor all‐Pb‐alloy design are described in detail. The resultant nominal chip access time and power are, respectively, 970 ps and 10 mW.

ISSN:0021-8979    

DOI:10.1063/1.336303

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

Indium‐doped zinc oxide films have been prepared by rf magnetron sputtering, using ZnO targets containing up to 10 wt. % In2O3. Room temperature resistivity of the deposited films was found to decrease by about four orders of magnitude as the In2O3content was increased from 0 to 10 wt. %.

ISSN:0021-8979    

DOI:10.1063/1.335962

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

The current oscillation was observed in modulation‐doped GaInAs/n‐GaAs strained‐layer superlattices when a high electric field was applied parallel to the layers. The critical voltage for the threshold of oscillation depended on the layer thickness. Observation of the propagation of a high‐electric‐field domain in the GaInAs layers shows that this phenomenon is the Gunn effect. Comparing with the high‐field effects in GaAs/n‐AlGaAs superlattices, we consider the role of the interface dislocations.

ISSN:0021-8979    

DOI:10.1063/1.335936

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

Very fast ion reactions can be studied with a time resolution better than 10−13s in a time‐of‐flight spectrometer by using a time amplification method. This is done by separating the system into a very short ion acceleration‐reaction section and a very long field‐free‐flight section. An example drawn from a study of field dissociation by atomic tunneling of RhHe2+is presented.

ISSN:0021-8979    

DOI:10.1063/1.335937

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

Zirconium dioxide (ZrO2) films have been grown on Si(100), Si(111), and SiO2/Si substrates heated at the range from room temperature to 800 °C by vacuum evaporation. X‐ray diffraction and reflection high‐energy electron diffraction observations reveal the epitaxial growth of tetragonal ZrO2(200) films on Si(100) substrates at 800 °C. The epitaxial imperfection is caused by preferentially oriented tetragonal ZrO2(002) grains. The crystalline system of ZrO2films depends on the substrate temperature. The crystalline perfection and the orientation of tetragonal ZrO2films grown at 800 °C depend on the substrate orientation.

ISSN:0021-8979    

DOI:10.1063/1.335912

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

Measurements of Ga‐As liquidus composition versus temperature in the range 350–650 °C are reported. The data are described by a constant interaction parameter &agr;≊−3600±1200 cal/mole in this range, rather than the temperature dependent value of &agr; required to fit available higher‐temperature data.

ISSN:0021-8979    

DOI:10.1063/1.335913

出版商:AIP    

年代:1985

数据来源: AIP