Production of porous silicon and studying its electrical properties

Other Title(s)

إنتاج السليكون المسامي و دراسة خصائصه الكهربائية

Dissertant

al-Jafar, Mukram Abd al-Muttalib Fakhri

Thesis advisor

al-Awsi, Bassam Ghalib Rashid

Comitee Members

Rashid, Hayfa Gh.
Mahdi, Muhammad S.
Husayn, Muhammad T.

University

University of Technology

Faculty

-

Department

Department of Laser Engineering and Electronic Optics

University Country

Iraq

Degree

Master

Degree Date

2007

English Abstract

In the present work, the construction of PS/C-Si heterojunction has been carried out using p-type (111) Silicon substrate with different resistivity.

A porous silicon layer has been prepared by electrochemical etching process in different HF acid concentrations using different electrical DC current densities for different etching times.

The morphological, electrical and optical properties of the porous silicon layer are studied for the range of current density (10-100) mA/cm2 for two p-type silicon resistivities (3.75*10-3 Ω.cm and 2.179 Ω.cm).

Increasing the current density from 20 to 40 mA/cm2 leads to shift the photoluminescence peak position from (2.28 to 2.29) eV.

Further increasing in current density up to 60 mA/cm2 reduces the PL peak intensity, for a highly doped p-type silicon of 3.75*10-3Ω.cm.

The photoluminescence gets blue shifted toward higher energy.

Formation current density plays a significant role to control the porous morphology where a change in the flat surface of crystalline silicon to relatively rough surface at small current density has been observed.

Increasing the current density to about 10 mA/cm2 produces more uniform porous layer, while small feature at the top of the porous layer formed at 20mA/cm2.

Optimum case for the surface morphology of the produced porous layer was achieved at 60 mA/cm2.

Studying the effect of etching time reveals that (30 min) etching time leads to form with a remarkable ordered porous structure, while different HF concentrations (10-40) % show that a mud-like structure which is considered as an optimum case for the surface morphology could be obtained when a 30% HF concentration was used.

Moreover, the effect of the formation current density on the J-V charactarestics shows that the passing current density with an applied voltage dicreases as the formation curent density increases.

Minimum J-V characterestics are observed at formatin current density of (60 mA/cm2 , 40 mA/cm2) for (3.75*10-3 Ω.cm, 2.179 Ω.cm) resistivity substrate respectively.

The electical propertiers reveal that the prepared device has a good linearity and of abrubt type.

While the electronic properties show that the formation of a heterojunction completely overlap with such a forbidden gap of the two material then.

Thereby we could get a staggered.

Device sensitivity and quantum effencitiy have been investigated and the result shows that the peak wave length appears at (850nm).

Main Subjects

Information Technology and Computer Science

No. of Pages

87

Table of Contents

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• MLA
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Language

English

Data Type

Arab Theses

Record ID

BIM-749058