摘要:

Time‐resolved photoconductivity measurements with subnanosecond time resolution are applied to study the electric field profile in amorphous silicon solar cells in the range from 0.3 V forward to 0.8 V reverse bias. The method is used for a comparison of state‐of‐the art devices with different junction design. Optical and electrical contributions to the device performance are discussed and the limitations in improving the performance by use ofa‐SiC:H window layers are pointed out.

ISSN:0003-6951    

DOI:10.1063/1.103672

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Ap‐doped confinement layer was fabricated by Be implantation for an InP/InGaAs/InP:Fe heterojunction field‐effect transistor (HFET). The epitaxial layers were grown by metalorganic vapor phase epitaxy and were suitable for the integration with apinphotodiode. Thepnjunction of the gate was formed by Zn diffusion that is not influenced by the preceding ion implantation. In the output characteristics of the HFET the pinch‐off voltage changes fromVp=−7 V without toVp=−3.5 V with confinement layer. No degradation of the maximum transconductance was observed. The gate leakage current is 80 nA at a gate source voltage ofVgs=−5 V.

ISSN:0003-6951    

DOI:10.1063/1.103648

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Hydrogenated amorphous silicon films were deposited by the direct photolysis of disilane using windowless hydrogen discharge. Electrical and optical properties of the films have been investigated. The photosensitivity (&sgr;ph/&sgr;d) is about 107in the films prepared at 250 °C, better than that of films obtained by conventional rf plasma chemical vapor deposition.

ISSN:0003-6951    

DOI:10.1063/1.103627

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

The minority‐electron diffusion length in commercialn+psilicon solar cells was determined from measurements of transient photocurrent generated by low‐energy x rays. The results show an order of magnitude increase in diffusion length over a time interval inversely proportional to the square of the injection rate. This accounts for the occurrence of dose rate sensitivity of silicon detectors of x rays at very low injection rates. The strong rate dependence observed suggests a space‐charge trapping mechanism.

ISSN:0003-6951    

DOI:10.1063/1.103628

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

We have investigated for the first time the propagation of the avalanche multiplication over the area ofp‐njunctions reverse biased above the breakdown voltage. The multiplication process spreads from the point where the avalanche is triggered to the whole junction area with a speed proportional to the final steady‐state value of the avalanche current. The values of the propagation speed suggest that the phenomenon is due to diffusion of carriers assisted by avalanche multiplication. This effect strongly affects the rise of the avalanche current and turns out to limit the performance of single photon avalanche diodes.

ISSN:0003-6951    

DOI:10.1063/1.103629

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

We have grown modulation‐doped AlInAs/InP heterostructures with two‐dimensional electron gases. Hall measurements and Shubnikov‐de Haas oscillations observed in these heterostructures yield electron mobilities as high as 26000, 9000, 2300 cm2/V s at 2, 77, and 300 K, with electron concentrations as high as 1.5×1012cm−2. These results demonstrate the potential of the AlInAs/InP heterostructure for power microwave applications.

ISSN:0003-6951    

DOI:10.1063/1.103630

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

We report the growth by low‐pressure metalorganic vapor phase epitaxy of lattice‐matched InGaAs on InP substrates using tertiarybutylarsine as the arsenic source. The grown layers are uniform in composition and are consistentlyntype with low background carrier concentrations (2–3×1015/cm3). Room‐temperature mobility as high as 11 200 cm2/V s with a corresponding 77 °K mobility of 57 000 cm2/V s are measured. Photoluminescence gave a strong narrow peak with a full width half maximum=3.1 meV, with no evidence of carbon incorporation.

ISSN:0003-6951    

DOI:10.1063/1.103631

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

The spatial resolution of the capacitance‐voltage profiling technique on semiconductors with one‐dimensional quantum confinement is shown to be given by the spatial extent of the wave function. The Debye length limitation does not apply. Capacitance‐voltage profiles on &dgr;‐doped GaAs of density 4–4.5×1012cm−2exhibit widths of 20 and 48 A˚ forp‐ andn‐type impurities, respectively. The profiles agree with the theoretical resolution function and with Be and Si profiles measured by secondary‐ion mass spectroscopy. It is further shown that the saturation of the free‐carrier density of highly Si &dgr;‐doped GaAs grown by molecular beam epitaxy is due to inactive Si impurities

ISSN:0003-6951    

DOI:10.1063/1.103632

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

We have found that Au‐contacted InP is chemically unstable at room temperature in a humid ambient due to the leaching action of indium nitrate islands that continually remove In from the contact metallization and thus, in effect, from the InP substrate. While similar appearing islands form on Au‐contacted GaAs, that system appears to be stable since leaching of the group III element does not take place.

ISSN:0003-6951    

DOI:10.1063/1.103633

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

The first successful demonstration of long‐wavelength infrared (LWIR) detection with a Kastalsky‐type AlGaAs/GaAs superlattice structure is reported. The experimental response band of the detector is centered near 10 &mgr;m in very good agreement with the theoretical response band provided that electron‐electron interactions are taken into account. The detector operates at significantly lower bias voltage than photoconductive multiple quantum well LWIR detectors. This could lead to important advantages in applications to photovoltaic detector arrays. The response at 83 K is about 50% of the response at 24 K. Optimization of the response, operating temperature, or bias voltage has not been carried out.

ISSN:0003-6951    

DOI:10.1063/1.103634

出版商:AIP    

年代:1990

数据来源: AIP