Subject : education



Download 3.89 Mb.
Page14/39
Date09.11.2016
Size3.89 Mb.
1   ...   10   11   12   13   14   15   16   17   ...   39

ABSTRACT

For this study 50 B.A students and 50 B.Com students who were studied and Arts &mCommerce College Mendarda , were selected and Arts &mCommerce College Mendarda , were selected for the study. To test Achievement Motivation the through Questionnaire. Achievement Motivation. OF B.A. students was seen more than B.Com students. Received’t ratio was 29.91 which was found not significant at 0.05 level. It shows that B.A. students Achievement Motivation. was good than B.Com students. Achievement Motivation. of B.A. students was seen more than B.Com students.


INTRODUCTION

Achievement Motivation is a mathematical formula that is supposed to be a measure of person’s Achievement Motivation. When it was first created, it was defined as the ration of mental age to chronological age multiplied by 100. Psychologists decide that it is better look at relative Achievement Motivation. score-hoe a person scores relative to other people the same age. Now people get assigned an average score of 100 and then we compare their actual scores on the series of Achievement Motivation tests to this average score in terms in of S.D.


Research Methodology- for this study 50 B.A. Students and 50 B.Com. student who were studied and Arts &Commerce College Mendarda , were selected for the study. The test of Achievement Motivation. evaluated through primary data i.e. Questionnaire. Achievement Motivation. Of B.A. students was seen more than B.Com students. It was. For statistical analysis t– test was used carried out.
HYPOTHESIS

there is no significant difference in Achievement Motivation. between B.A. students and B.Com students


RESULTS AND FINDINGS

Table : 1, Mean, Mean Difference, Standard Deviation and “t” value of B.A students and B.Com. Students in. Achievement Motivation

Component

N

Group

Mean

S.D

t”

Level of significance

Achievement Motivation

50

50

B.A

B.Com

116.66

112.83

6.07

8.71


29.91


0.05

Achievement Motivation mean of B.A. Students and B.Com students was 116.66 and 112.83 respectively. S.D. was . Received Achievement Motivation standard deviation of B.A. Students and B.Com students was 6.07and 8.71 reactively ‘t’ ratio was 29.91 which was found not significant at 0.05 level. Therefore, the null hypothesis was rejected . It indicates that there is significant difference in Achievement Motivation.of B.A students and B.Com students. It shows that B.A students was good than B.Com students. Achievement Motivation. of B.A. students was been more than B.Com. students.
CONCLUSION

Achievement Motivation is a score derived from one of several standardized test designed to assess Achievement Motivation. It scored are used as predictors od educational achievement, special needs, job performance and income. They are also used to study Achievement Motivation distributions in populations and the correlations between Achievement Motivation. and other variables. It is disputed these changes in scores reflect real changes in intellectual abilities. Health is important in understanding differences in Achievement Motivation. test scores and other measures of cognitive ability.


REFERENCES

  1. Philip G improve your Knowledge by publishaed by mark publishers jaipur

  2. Stastical anlysis by S..N. Gupta by publishaed S.N.Chand new Delhi.






Applications of Semiconductor Alloys in PHOTONIC Devices




Prof Vedam RamaMurthy1,

Prof and Head of the Department, T.J.P.S College, Guntur, Andhra Pradesh, India



Alla Srivani 2

Assistant Professor in Vasi Reddy Venkatadri Institute of Technology (VVIT), Guntur, Andhra Pradesh, India



G Veeraraghavaiah3

Assistant professor, P.A.S College, Pedanandipadu, Guntur, Andhra Pradesh, India



KEYWORDS: Semiconductor Alloys. III-V Group, Antimonide Group, Photonic devices

Abstract:

Semiconductor substrates offer the opportunity of integrating electronic devices with photonic components. Si is ideal for electronic circuits but it has limited function for photonics. It is an excellent detector for wavelength less than 1 micron but it doesn't work in the transmission window of glass fiber. It doesn't generate light efficiently except in the form of porous silicon. The emission wavelength doesn't match with fiber either. Compound semiconductors containing group III and group V elements are best candidates. III-V compound semiconductors include binary (2 elements), ternary (3 elements), and quarternery (4 elements) materials. By integrating electronic devices with photonic components, it is possible to realize single-chip transceivers with low cost and high reliability.


Introduction:

The effort of integrated photonic circuit started twenty years ago using GaAs as the substrate. There are quite a few combinations to form III-V and II-VI compounds, e.g., GaAs, InGaAs, InGaAsP, GaN, CdSe, HgTe, etc. Some of the binary compounds are available commercially as substrate materials. However, ternary and quarternery materials can only be grown epitaxially. The growth of planar films on a substrate is called epitaxy. To grow high quality films with low defect, the lattice structure and dimension must match. If the dimensions do not match, there is


strain. Only very thin layers can be grown. It is called strained-layer films. There are two binary substrates of great importance, namely, GaAs and InP. GaAs is reasonably well matched to AlAs, therefore, AlGaAs can be grown on GaAs perfectly. It forms the basis of many novel electronic devices. On the other hand,

InGaAs and InGaAsP can be grown on InP with no lattice mismatch. It is the basis of photonic components used in optical communications systems. The newest development is GaN.


It may become the material system for optical memory and display in the near future. GaN can emit at short wavelengths and may be extended to cover most of the visible region. To grow compound semiconductor films, molecular beam epitaxy (MBE), metalorganic chemical vapor deposition (MOCVD), and liquid phase epitaxy (LPE) are used. MBE involves a high vacuum system. The source material is heated up until an adequate vapour pressure is established. The evaporated molecules travel through the vacuum and get deposited on the substrate. The molecules migrate and relax on the surface until a crystalline site is found. If the substrate is too hot, it may also re-evaporate from the surface. Since high vacuum is used, there are many diagnostic tools available for in-situ control, for example, high energy electron diffraction (HEED). From the diffraction pattern, one can monitor the growth process and the quality of the film. MBE is a slow but extremely well-controlled process. You can grow films with a single-layer accuracy. MOCVD can be performed at low pressure or at the atmospheric pressure. The source materials include arsine, phosphine, organometallic compounds, such as tri-methyl gallium, di-ethyl indium, etc. They are either extremely toxic or highly flammable. Precaution must be exercised in performing MOCVD. It can be scaled up for industrial production. Using low pressure MOCVD, the film accuracy can be controlled to within two monolayers.

Refractive index

The refractive index of semiconductors represents a fundamental physical parameter that characterizes their optical and electronic properties. It is a measure of the transparency of the semiconductor to incident spectral radiation. In addition, knowledge of the refractive index is essential for devices such as photonic crystals, wave guides, solar cells and detectors. [9]


The refractive index values of Arsenide Semiconductor alloys are evaluated by using additivity and quadratic expressions of the equations 4.1 to 4.3 by replacing A by n the refractive index from the reported values of Refractive index of Binary Semiconductors.
LPE is a low-cost approach to growing compound semiconductors. A graphite boat carries the substrate to different wells containing molten liquids of various compositions. It is only good for film thickness above 1000 Å. Since most advanced photonic components involve quantum wells with a thickness below 20 nm, it is no longer a viable epitaxial system. By stacking layers of different compositions together, we can form a periodic structure. If the period is too thick, there is no interaction among electrons residing in different layers. However, if the layers are below 20 nm, electrons in different layers may tunnel and interact. Such an artificial, periodic structure is called superlattice. Quantum wells and superlattices offer new electrical and optical properties not available from traditional solid state materials.

n12=n1*x+n2*(1-x) + 1/1000*SQRT (n1*n2)*x*(1-x) (1)

Method 2

n12=n1*x+n2*(1-x) +1/1000* SQRT (n1*n2*x*(1-x)) (2)

Method 3

n12=n1*x+n2*(1-x) – 1/1000*SQRT (n1*n2)*x*(1-x) (3)

Method 4

n12=n1*x+n2*(1-x) – 1/1000*SQRT (n1*n2*x*(1-x)) (4)

Additivity

n12=n1*x+n2*(1-x) (5)

Compound

Energy

Gap

Eg (ev)

Wave

Length

Λ

Refractive

Index

N







Optical__Polarizability__AlSb'>Optical

Polarizability

AlSb

3.0

2.9

2.8

2.7

2.6

2.5

2.4

2.3

2.2

2.1



4133

4276

4429

4593

4769

4960

5167

5391

5636

5905



4.52

4.66

5.27

5.08

4.81

4.61

4.44

4.31

4.2

4.01



0.284

0.273

0.234

0.245

0.262

0.277

0.290

0.302

0.312

0.332



5.854

5.469

5.098

4.740

4.397

4.065

3.746

3.441

3.148

2.868



Calculated

107.6


Reported

125.65





Compound

Energy

Gap

Eg (ev)

Wave

Length

λ

Refractive

Index

N







Optical

Polarizability

GaSb


3.0

2.9

2.8

2.7

2.6

2.5

2.4

2.3

2.2

2.1



4133

4276

4429

4593

4769

4960

5167

5391

5636

5905



3.732

3.728

3.76

3.836

3.984

4.312

4.513

4.492

4.521

4.705



0.366

0.366

0.362

0.352

0.335

0.301

0.284

0.286

0.284

0.269



5.8548

5.469

5.098

4.74

4.397

4.065

3.746

3.441

3.148

2.868



Calculated

27.05


Reported

30.54

Download 3.89 Mb.

Share with your friends:
1   ...   10   11   12   13   14   15   16   17   ...   39




The database is protected by copyright ©sckool.org 2020
send message

    Main page