Amorphous superlattice structures with carbon as a wide bandgap component

Author(s):  
R. Mazurczyk ◽  
M. Gazicki
1986 ◽  
Vol 70 ◽  
Author(s):  
Rajeewa R. Arya ◽  
Anthony Catalano ◽  
James O'dowd

ABSTRACTSuperlattice doped layers of the type ABABAB … have been prepared where A is the wide bandgap a-Si:C:H doped layer and B is the narrow bandgap a-Si:C:H or a-Si:H doped layer. The bandgaps of the individual layers were modulated by changing the gas phase composition of methane during the plasma deposition. By varying the structure of the films, superlattice p-layers with resistivities in the range of 106 - 107 ohm-cm with optical bandgaps of 2.0 - 2.4 eV, and activation energies of 0.35 - 0.48 eV and superlattice n-layers with resistivities in the range of 104 - 105 ohm-cm with optical bandgaps of 1.86 - 2.03 eV and activation energies of 0.38 - 0.47 eV have been obtained.P-I-N solar cells have been prepared with both p and n layers comprised of superlattice structures. Conversion efficiencies as high as 10.86% have been achieved under simulated AM1.5 Global conditions. Measurements reveal a marked improvement in both built-in voltage and carrier collection length.


2001 ◽  
Vol 9 (1-2) ◽  
pp. 21-29
Author(s):  
R. Mazurczyk ◽  
M. Gazicki-Lipman ◽  
T. Wagner

Author(s):  
F. A. Ponce ◽  
R. L. Thornton ◽  
G. B. Anderson

The InGaAlP quaternary system allows the production of semiconductor lasers emitting light in the visible range of the spectrum. Recent advances in the visible semiconductor diode laser art have established the viability of diode structures with emission wavelengths comparable to the He-Ne gas laser. There has been much interest in the growth of wide bandgap quaternary thin films on GaAs, a substrate most commonly used in optoelectronic applications. There is particular interest in compositions which are lattice matched to GaAs, thus avoiding misfit dislocations which can be detrimental to the lifetime of these materials. As observed in Figure 1, the (AlxGa1-x)0.5In0.5P system has a very close lattice match to GaAs and is favored for these applications.In this work, we have studied the effect of silicon diffusion in GaAs/InGaAlP structures. Silicon diffusion in III-V semiconductor alloys has been found to have an disordering effect which is associated with removal of fine structures introduced during growth. Due to the variety of species available for interdiffusion, the disordering effect of silicon can have severe consequences on the lattice match at GaAs/InGaAlP interfaces.


Author(s):  
K. Ogura ◽  
A. Ono ◽  
S. Franchi ◽  
P.G. Merli ◽  
A. Migliori

In the last few years the development of Scanning Electron Microscopes (SEM), equipped with a Field Emission Gun (FEG) and using in-lens specimen position, has allowed a significant improvement of the instrumental resolution . This is a result of the fine and bright probe provided by the FEG and by the reduced aberration coefficients of the strongly excited objective lens. The smaller specimen size required by in-lens instruments (about 1 cm, in comparison to 15 or 20 cm of a conventional SEM) doesn’t represent a serious limitation in the evaluation of semiconductor process techniques, where the demand of high resolution is continuosly increasing. In this field one of the more interesting applications, already described (1), is the observation of superlattice structures.In this note we report a comparison between secondary electron (SE) and backscattered electron (BSE) images of a GaAs / AlAs superlattice structure, whose cross section is reported in fig. 1. The structure consist of a 3 nm GaAs layer and 10 pairs of 7 nm GaAs / 15 nm AlAs layers grown on GaAs substrate. Fig. 2, 3 and 4 are SE images of this structure made with a JEOL JSM 890 SEM operating at an accelerating voltage of 3, 15 and 25 kV respectively. Fig. 5 is a 25 kV BSE image of the same specimen. It can be noticed that the 3nm layer is always visible and that the 3 kV SE image, in spite of the poorer resolution, shows the same contrast of the BSE image. In the SE mode, an increase of the accelerating voltage produces a contrast inversion. On the contrary, when observed with BSE, the layers of GaAs are always brighter than the AlAs ones , independently of the beam energy.


2019 ◽  
Author(s):  
Ulrich W. Paetzold ◽  
Saba Gharibzadeh ◽  
Marius Jackoby ◽  
Tobias Abzieher ◽  
Somayeh Moghadamzadeh ◽  
...  

2019 ◽  
Author(s):  
Yuliar Firdaus ◽  
Thomas D. Anthopoulos ◽  
Yuanbao Lin ◽  
Ferry Anggoro Ardy Nugroho ◽  
Emre Yengel ◽  
...  

Author(s):  
Sheng-Chieh Lin ◽  
Yu-Chieh Cheng ◽  
Man-Kit Leung ◽  
Jiun-Haw Lee ◽  
Tien-Lung Chiu

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