Determination of conduction band tail and Fermi energy of heavily Si‐doped GaAs by room‐temperature photoluminescence

1995 ◽  
Vol 78 (5) ◽  
pp. 3367-3370 ◽  
Author(s):  
Nam‐Young Lee ◽  
Kyu‐Jang Lee ◽  
Chul Lee ◽  
Jae‐Eun Kim ◽  
Hae Yong Park ◽  
...  
Keyword(s):  
Conduction Band ◽  
Fermi Energy ◽  
Room Temperature ◽  
Band Tail ◽  
Room Temperature Photoluminescence ◽  
Si Doped

Recombination and Electronic Transport in Low-Gap a-Si,Ge:H,F Alloys

1987 ◽  
Vol 95 ◽  
Author(s):  
S. Aljishi ◽  
D. S. Shen ◽  
V. Chu ◽  
Z E. Smith ◽  
J. P. Conde ◽  
...  
Keyword(s):  
Conduction Band ◽  
Electronic Transport ◽  
Room Temperature ◽  
Dark Conductivity ◽  
Electron Trapping ◽  
Conduction Band Edge ◽  
Band Tail ◽  
Intensity Dependence ◽  
Defect Densities ◽  
Deposition Conditions

AbstractWe have studied the temperature and intensity dependence (130K to 300K) of photo- and dark conductivity in a series of low-gap a-Si,Ge:H,F alloys (Eopt=1.25 to 1.33 eV) prepared under different deposition conditions. Electron time of flight experiments were conducted between 300K and 400K. Results reveal an increase in the slope of the exponential conduction band tail to ∼ 50 meV and a peak in electron trapping states at 0.3 to 0.4 eV below the conduction band edge, leading to a transition from extended to hopping conduction by electrons at slightly below room temperature. The alloys have midgap defect densities in the low 1017 cm−3eV−1 range.

Hydrogenation of Gallium Nitride

1993 ◽  
Vol 325 ◽  
Author(s):  
M. S. Brandt ◽  
N. M. Johnson ◽  
R. J. Molnar ◽  
R. Singh ◽  
T. D. Moustakas
Keyword(s):  
Comparative Study ◽  
Conduction Band ◽  
Room Temperature ◽  
Hole Concentration ◽  
Conduction Band Edge ◽  
Order Of Magnitude ◽  
Si Doped ◽  
Donor State ◽  
P Type ◽  
Mg Doped

AbstractA comparative study of the effects of hydrogen in n-type (unintentionally and Si-doped) as well as p-type (Mg-doped) MBE-grown GaN is presented. Hydrogenation above 500°C reduces the hole concentration at room temperature in the p-type material by one order of magnitude. Three different microscopic effects of hydrogen are suggested: Passivation of deep defects and of Mg-acceptors due to formation of hydrogen-related complexes and the introduction of a hydrogenrelated donor state 100 meV below the conduction band edge.

Plasma Edge Reflectance Measurements in GaxIn(1−x)As and InAsxSb(1−x) Alloys

1971 ◽  
Vol 49 (15) ◽  
pp. 2052-2060 ◽  
Author(s):  
Mathew B. Thomas ◽  
John C. Woolley
Keyword(s):  
Experimental Data ◽  
Relaxation Time ◽  
Effective Mass ◽  
Conduction Band ◽  
Room Temperature ◽  
Plasma Edge ◽  
Electron Effective Mass ◽  
Reflectance Measurements ◽  
Type Conduction

Room temperature measurements of plasma reflectance have been made on polycrystalline homogeneous n type samples of GaxIn(1−x) As and InAsxSb(1−x) alloys. An analysis for the case of general degeneracy in a Kane-type conduction band has been developed, to allow the determination of electron effective mass (m0*/m) at the bottom of the conduction band. Hence values of m0*/m vs. x have been determined for both alloy systems. From the experimental data, values of relaxation time and optical mobility have also been calculated.

Interactions Between Al and Cr Thin Films

1976 ◽  
Vol 34 ◽  
pp. 638-639
Author(s):  
R. M. Anderson ◽  
T. M. Reith ◽  
M. J. Sullivan ◽  
E. K. Brandis
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Vacuum System ◽  
Processing Temperature ◽  
Diffusion Couples ◽  
Electronic Circuits ◽  
Intermetallic Formation ◽  
Si Substrates ◽  
Aluminum Silicon

Thin films of aluminum or aluminum-silicon can be used in conjunction with thin films of chromium in integrated electronic circuits. For some applications, these films exhibit undesirable reactions; in particular, intermetallic formation below 500 C must be inhibited or prevented. The Al films, being the principal current carriers in interconnective metal applications, are usually much thicker than the Cr; so one might expect Al-rich intermetallics to form when the processing temperature goes out of control. Unfortunately, the JCPDS and the literature do not contain enough data on the Al-rich phases CrAl7 and Cr2Al11, and the determination of these data was a secondary aim of this work.To define a matrix of Cr-Al diffusion couples, Cr-Al films were deposited with two sets of variables: Al or Al-Si, and broken vacuum or single pumpdown. All films were deposited on 2-1/4-inch thermally oxidized Si substrates. A 500-Å layer of Cr was deposited at 120 Å/min on substrates at room temperature, in a vacuum system that had been pumped to 2 x 10-6 Torr. Then, with or without vacuum break, a 1000-Å layer of Al or Al-Si was deposited at 35 Å/s, with the substrates still at room temperature.

STEM and ELS Observation of Early Oxide Formation on the Surface of Cr Thin Films

1980 ◽  
Vol 38 ◽  
pp. 412-413
Author(s):  
Fumio Watari ◽  
J. M. Cowley
Keyword(s):  
Thin Films ◽  
Optical System ◽  
Room Temperature ◽  
Oxide Formation ◽  
Initial Nucleation ◽  
Diffraction Patterns ◽  
Relationship Of ◽  
Multiple Twinning ◽  
Moderately High Temperature

STEM coupled with the optical system was used for the investigation of the early oxidation on the surface of Cr. Cr thin films (30 – 1000Å) were prepared by evaporation onto the polished or air-cleaved NaCl substrates at room temperature and 45°C in a vacuum of 10−6 Torr with an evaporation speed 0.3Å/sec. Rather thick specimens (200 – 1000Å) with various preferred orientations were used for the investigation of the oxidation at moderately high temperature (600 − 1100°C). Selected area diffraction patterns in these specimens are usually very much complicated by the existence of the different kinds of oxides and their multiple twinning. The determination of the epitaxial orientation relationship of the oxides formed on the Cr surface was made possible by intensive use of the optical system and microdiffraction techniques. Prior to the formation of the known rhombohedral Cr2O3, a thin spinel oxide, probably analogous to γ -Al203 or γ -Fe203, was formed. Fig. 1a shows the distinct epitaxial growth of the spinel (001) as well as the rhombohedral (125) on the well-oriented Cr(001) surface. In the case of the Cr specimen with the (001) preferred orientation (Fig. 1b), the rings explainable by spinel structure appeared as well as the well defined epitaxial spots of the spinel (001). The microdif fraction from 20A areas (Fig. 2a) clearly shows the same pattern as Fig. Ia with the weaker oxide spots among the more intense Cr spots, indicating that the thickness of the oxide is much less than that of Cr. The rhombohedral Cr2O3 was nucleated preferably at the Cr(011) sites provided by the polycrystalline nature of the present specimens with the relation Cr2O3 (001)//Cr(011), and by further oxidation it grew into full coverage of the rest of the Cr surface with the orientation determined by the initial nucleation.

Sign in / Sign up

Export Citation Format

Share Document