摘要:

The mobility‐lifetime products ( &mgr;&tgr;) and interface property have been examined through the photovoltaic studies in actual hydrogenated amorphous silicon (a–Si:H)p–i–njunction solar cells. A small amount of boron atoms included ina–Si:H enhances the &mgr;&tgr; products of both electrons and holes up to the order of 10−7cm2/V, which corresponds to the carrier diffusion length in excess of 5000 A˚. The doped window layer possessing inferior photoelectric property works as the recombination region for photocarriers generated in the activeilayer, and practically dominates the interface property together with the surface recombination velocityS0at the electrode/doped layer interface. TheS0at the SnO2/pa–Si:H interface is estimated to be about 3×102cm/s with an assumption of the electron mobility at 0.1 cm2/Vs. Prolonged light exposure causes a reversible change of the &mgr;&tgr; products in every layer composing thep–i–njunction. These experimental results are discussed in connection with photovoltaic performances.

ISSN:0021-8979    

DOI:10.1063/1.332485

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

We have developed a computer program to calculate the field effect conductance for an amorphous semiconductor including the effects of surface states and fixed charge atbothsurfaces of the thin semiconductor film. For undoped films with a bulk density of states of less than 1017cm−3eV−1, the space‐charge region extends to a depth of 0.5 &mgr;m. A complete description of the potential distribution in the semiconductor must include the contribution of surface charge from the surfaceoppositethe gate electrode. This is of practical importance in thin film transistors, for example, where different transistor structures and processing of devices can affect the charge density of this surface.

ISSN:0021-8979    

DOI:10.1063/1.332486

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Two semi‐insulating liquid‐encapsulated Czochralski GaAs cyrstals, one Cr‐doped and the other undoped, were annealed at 750 °C for 15 min in flowing H2. Each sample converted to conductingptype in the near‐surface region, due to the formation of acceptors atEv+0.1 eV. We have studied this phenomenon by electrical, optical, and analytical profiling techniques, and have determined conclusively that the acceptors in our samples arenotrelated to Mn accumulation, a commonly accepted explanation. It is argued that the 0.1‐eV center may arise from several possible sources, each exhibiting a VGa‐like state at this energy.

ISSN:0021-8979    

DOI:10.1063/1.332487

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Polyacetylene/polysiloxane interface states have been investigated using metal‐insulator‐semiconductor (MIS) diodes. The 1‐mm2MIS diodes (Al/polysiloxane/polyacetylene) have been fabricated by use of a conventional photolithographic technique. TheI‐VandC‐Vmeasurements were used to explore the polyacetylene/polysiloxane interface electrical properties. The electrical conduction mechanism in this interface was found to be a Schottky‐Richardson mechanism. Using theC‐Vmeasurements to determine the interface states density distribution, it was found that the distribution had aUshape in the gap and its minimum value was 6×1013eV−1 cm−2. An attempt was made to fabricate an insulating gate field‐effect transistor which worked as a depletion‐type transistor with a very low transconductance,gm=13 n&OHgr;−1.

ISSN:0021-8979    

DOI:10.1063/1.332488

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

The electrical and structural properties of contact obtained onp‐type cadmium telluride by electroless deposition of gold from a chloride solution have been investigated by means of current‐voltage measurements and ion beam analysis (Secondary Ion Mass Spectrometry and Rutherford Backscattering). On high resistivity material, the ohmic behavior of these contacts has been found strongly dependent on the time of reaction between AuCl3and CdTe and can be interpreted in terms of a current flow enhanced by tunnelling through the Au–CdTe barrier. This enhancement results from the diffusion of dopant gold atoms into the semiconductor, a distance of a few tens of nanometers below the interface.

ISSN:0021-8979    

DOI:10.1063/1.332435

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

The effects of the deposition temperature on the interaction of the hydrogenated amorphous silicon films with indium–tin–oxide and tin–oxide films have been investigated in the temperature range 150–300 °C, using Auger electron spectroscopy, secondary ion mass spectrometry, and scanning electron microscopy. It was found that the constituent atoms such as indium and tin are detected in the thin amorphous silicon films deposited. Around the interface between the transparent conductive films and amorphous silicon films the formation of oxidized silicon was also observed. The depth distributions of indium in the amorphous silicon films are strongly dependent upon the deposition temperature while those of tin are almost independent. From results on the observation of the surface morphology of the amorphous silicon films, it has been shown that those depth distributions may be much affected by the initial covering over substrates with the amorphous silicon films.

ISSN:0021-8979    

DOI:10.1063/1.332436

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Surface damage in Si substrates created by Ar‐ion milling or by reactive‐ion etching in CF4, CHF3, Cl2, SiCl4, or SiF4has been investigated. Metal‐oxide‐semiconductor capacitors were fabricated on the etched Si substrates, and the interface‐state densities were obtained from capacitance‐voltage measurements. Interface states generated by the dry etching processes were strongly dependent on the etching gas and the bias voltage. Carbon‐based gases (CF4, CHF3) induced more interface states than those without carbon. For the carbon‐based gases, Si samples etched in CHF3showed lower densities of interface states than samples etched in CF4under the same conditions. Generation lifetime measurements indicated that samples with large densities of interface states also had short lifetimes. Measurements of oxidation‐induced stacking faults caused by dry etching were consistent with both the interface‐state and lifetime measurements. Thermal annealing of the etched wafers was not effective in reducing the surface damage. The measured interface states on the dry etched Si substrates could be lowered to their pre‐etched levels by removing at least 500 A˚ of the etched surface by wet chemical etching.

ISSN:0021-8979    

DOI:10.1063/1.332437

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

The microstructure and programming mechanism of an electrically programmable antifuse is described. The device consists ofn+pn+junctions in polycrystalline silicon programmed by applying voltage pulses to the twon+terminals. High voltage electron microscopy and optical microscopy reveal the micro‐structure of programmed antifuses. Devices with Al metallization can be programmed with a single long pulse. The final resistance is about 20&OHgr; and a metallic aluminum spike is formed between the two contacts. With Al and TiW (barrier) metallization, programming occurs after a series of short pulses by migration ofn+dopant. This results in an ohmic contact between the twon+regions with a final resistance of approximately 300&OHgr;.

ISSN:0021-8979    

DOI:10.1063/1.332438

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

The electrical and optical properties of rf magnetron sputtered films of amorphous hydrogenated silicon (a–Si:H) have been measured as a function of rf power, argon and hydrogen partial pressures, and target‐substrate distance. The properties of the deposited films show a very different dependence on preparation conditions than those prepared by nonmagnetron sputtering. The conductivity can be varied over ten orders of magnitude and the optical gap can be shifted by more than 1.0 eV by changing the deposition parameters. Furthermore, it is found that the electrical conductivity and optical band gap are strongly correlated. Thus, we have not been able to prepare undoped films with a given conductivity independently of the optical gap. The results of our measurments of the temperature dependence of the conductivity, the conductivity activation energy (&Dgr;E&sgr;), the shape of the optical absorption curve, and the optical gap (Eopt), suggest a direct connection between gap state density and the optical gap.

ISSN:0021-8979    

DOI:10.1063/1.332439

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

The effects of microwave radiation on the vortex modes of Josephson tunnel junctions have been examined. Current steps are induced on the resistive branches at voltagesV=(n/m)(h&ngr;/2e) wherenandmare integers and &ngr; is the frequency of the incident radiation. The system we have studied is a well‐defined one in which vortices undergoing periodic motion interact with the periodic perturbation of the microwave radiation. Vertical steps are induced when resonance occurs.

ISSN:0021-8979    

DOI:10.1063/1.332440

出版商:AIP    

年代:1983

数据来源: AIP