A presentation on Molecular Beam Epitaxy made by Deepak Rajput. It was presented as a course requirement at the University of Tennessee Space Institute in Fall 2008.
A presentation on Molecular Beam Epitaxy made by Deepak Rajput. It was presented as a course requirement at the University of Tennessee Space Institute in Fall 2008.
Chemical Vapour Deposition is a Chemical Synthesis route of Nanomaterials. Specially thin films like Graphene and Carbon NanoTubes are grown by this method.
If you have any questions, contact me. I would be happy to help.
PLEASE LIKE IT AND GIVE COMMENT
In this presentation,
The author gives the working principle of the PVD and Sputtering methods. But you can also find an information about the thin film and plasma phase of a matter.
Also this is related with Magnetron Sputtering method.
Chemical Vapour Deposition is a Chemical Synthesis route of Nanomaterials. Specially thin films like Graphene and Carbon NanoTubes are grown by this method.
If you have any questions, contact me. I would be happy to help.
PLEASE LIKE IT AND GIVE COMMENT
In this presentation,
The author gives the working principle of the PVD and Sputtering methods. But you can also find an information about the thin film and plasma phase of a matter.
Also this is related with Magnetron Sputtering method.
A Presentation on Molecular Beam Epitaxy for college students . BTech 3rd Year Electronics and Communication Branch. Helping the students to make them free to do something productive rather than wasting time PPTs
Module PHY6002 Inorganic Semiconductor Nanostructures
Lectures 7, 8, 9 and 10
1
Lecture 7 – The fabrication of semiconductor
nanostructures I
Introduction
In this lecture we will look at the techniques used to fabricate semiconductor
nanostructures. The well-established epitaxial methods used to produce
quantum wells will be described. The main techniques applied to produce
quantum wires and quantum dots will be discussed, with a comparison of their
relative advantages and disadvantages. In the next lecture we will look in
detail at the most successful technique used to produce quantum dots, self-
organisation.
Epitaxial techniques
There are two well established epitaxial growth techniques used to produce
high quality quantum wells: molecular beam epitaxy (MBE) and metal organic
vapour phase epitaxy (MOVPE).
The following figure shows the main components of an MBE reactor.
The reactor consists of an ultra-high vacuum chamber with a number of
effusion cells, each containing a different element. Each cell has a mechanical
shutter placed in front of its opening. In operation the cells are heated to a
temperature where the elements start to evaporate, producing a beam of
atoms which leave the cells. These beams are aimed at a heated substrate
which consists of a thin wafer of a suitable bulk semiconductor. The incident
beams combine at the surface of the substrate and a semiconductor is
deposited atomic-layer by atomic-layer. The substrate is rotated to ensure
even growth over its surface. By opening the mechanical shutters in front of
certain cells it is possible to control which semiconductor is deposited. For
example opening the shutters in front of the Ga and As cells results in the
growth of GaAs. Shutting the Ga cell and opening the Al cell switches to the
growth of AlAs. Because the shutters can be operated very rapidly in
comparison to the rate at which material is deposited, it is possible to grow
An MBE reactor
Module PHY6002 Inorganic Semiconductor Nanostructures
Lectures 7, 8, 9 and 10
2
very thin layers with very sharp interfaces between layers. The following figure
shows a transmission electron microscope image of a quantum well sample
containing five wells of different thicknesses. The thinnest well has a
thickness of only 1nm. Other cells in the MBE reactor may contain elements
used to dope the semiconductor and it is possible to monitor the growth as it
proceeds by observing the electron diffraction pattern produced by the
surface.
The second epitaxial growth technique is metal organic vapour phase epitaxy
(MOVPE). In this technique the required elements are carried, as a
component of gaseous compounds, to a suitable chamber where they mix as
the gases flow over the surface of a heated substrate. The compounds
breakdown to deposit the semiconductor on the surface of the substrate with
the remaining waste gases being removed from the chamber. Valves in the
gas l ...
Nanophysics the physics of structures and artefacts with
dimensions in the nanometer range or of
phenomena occurring in nanoseconds. Nanoscience is the study of atoms, molecules and object whose size is of the nanometer scale (1-100nm).
Sachpazis:Terzaghi Bearing Capacity Estimation in simple terms with Calculati...Dr.Costas Sachpazis
Terzaghi's soil bearing capacity theory, developed by Karl Terzaghi, is a fundamental principle in geotechnical engineering used to determine the bearing capacity of shallow foundations. This theory provides a method to calculate the ultimate bearing capacity of soil, which is the maximum load per unit area that the soil can support without undergoing shear failure. The Calculation HTML Code included.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
Forklift Classes Overview by Intella PartsIntella Parts
Discover the different forklift classes and their specific applications. Learn how to choose the right forklift for your needs to ensure safety, efficiency, and compliance in your operations.
For more technical information, visit our website https://intellaparts.com
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
Courier management system project report.pdfKamal Acharya
It is now-a-days very important for the people to send or receive articles like imported furniture, electronic items, gifts, business goods and the like. People depend vastly on different transport systems which mostly use the manual way of receiving and delivering the articles. There is no way to track the articles till they are received and there is no way to let the customer know what happened in transit, once he booked some articles. In such a situation, we need a system which completely computerizes the cargo activities including time to time tracking of the articles sent. This need is fulfilled by Courier Management System software which is online software for the cargo management people that enables them to receive the goods from a source and send them to a required destination and track their status from time to time.
TECHNICAL TRAINING MANUAL GENERAL FAMILIARIZATION COURSEDuvanRamosGarzon1
AIRCRAFT GENERAL
The Single Aisle is the most advanced family aircraft in service today, with fly-by-wire flight controls.
The A318, A319, A320 and A321 are twin-engine subsonic medium range aircraft.
The family offers a choice of engines
Automobile Management System Project Report.pdfKamal Acharya
The proposed project is developed to manage the automobile in the automobile dealer company. The main module in this project is login, automobile management, customer management, sales, complaints and reports. The first module is the login. The automobile showroom owner should login to the project for usage. The username and password are verified and if it is correct, next form opens. If the username and password are not correct, it shows the error message.
When a customer search for a automobile, if the automobile is available, they will be taken to a page that shows the details of the automobile including automobile name, automobile ID, quantity, price etc. “Automobile Management System” is useful for maintaining automobiles, customers effectively and hence helps for establishing good relation between customer and automobile organization. It contains various customized modules for effectively maintaining automobiles and stock information accurately and safely.
When the automobile is sold to the customer, stock will be reduced automatically. When a new purchase is made, stock will be increased automatically. While selecting automobiles for sale, the proposed software will automatically check for total number of available stock of that particular item, if the total stock of that particular item is less than 5, software will notify the user to purchase the particular item.
Also when the user tries to sale items which are not in stock, the system will prompt the user that the stock is not enough. Customers of this system can search for a automobile; can purchase a automobile easily by selecting fast. On the other hand the stock of automobiles can be maintained perfectly by the automobile shop manager overcoming the drawbacks of existing system.
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
4. Epitaxy is the process of growing a thin crystalline layer on a crystalline
substrate.
Epitaxial layer is always thinner than the substrate
Epitaxial grow techniques:
What is epitaxy?
Vapor-Phase Epitaxy Liquid Phase-Epitaxy Molecular Beam Epitaxy
VPE is a modification of chemical vapor
deposition
LPE is a method to grow semiconductor
crystal layers from the melt on solid
substrates.
MBE is based on an UHV(Ultra High
Vacuum) technique.
Chemical reactions involved Chemical reactions involved No chemical reactions involved.
5. Homoepitaxy
The deposition substrate is the same material as we are depositing from the beam.
(e.g Si on Si)
Heteroepitaxy
Substrate and material are of different composition in order to fabricate integrated
crystalline layers of different materials. (e.g GaAs on Si)
Epitaxy types
6. There are three main growth modes that can occur depending upon the
substrate temperature, the deposition rate and available surface energy
Growth modes
8. • Pumping Systems
• Growth Chamber, epitaxial growth
happens.
• Load lock facilitates the
introduction and removal of
samples
• Auxiliary chamber host analytical
and process equipment
MBE system
9. Gas sources are heated in separate k-cells or
electron beam evaporators to achieve
molecular or atom beams.
No interaction with each other until they
reach the Surface.
During the deposition, the interactions of the
atoms produce the epitaxial growth.
MBE Growth process
10. Controlling , via shutters and the
temperature of the source, will
control the rate of impinging
materials.
The temperature of the substrate will
control the rate of diffusion and
desorption.
Background gases help to avoid
monolayr contamination.
MBE Growth process
11. Deposition rate (𝜇𝑚/ℎ𝑟): 1-5 s
Growth temperature (℃): 550
Thickness control (Å): 5
Interface width (Å): 5
Shuttering control: 0.1 s
MBE features
12. Reflection High Energy Electron Diffraction (RHEED)
Observe removal of contaminants from the substrate surface
Calibrate growth rates
Estimate the substrate temperature
Determine the stoichiometry
Analyze surface morphology – RHEED pattern
Study growth kinetics – RHEED intensity oscillations
In Situ Monitoring
14. Materials used on MBE
Different materials are used depending the type of MBE, but we will focus on
Solid Source MBE type.
Molecular Beams Substrate target
Group III – V molecular beams III-V Semiconductors
SS- MBE
Group II – VI molecular beams II-VI Semiconductors
Others IV-VI Semiconductors, Heusler alloys,
silicides, metals ...
Typically, the substrate target is a semiconductor material with useful electronic properties.
The molecular beam quite often is composed of evaporated elemental substances such as
gallium and arsenic
15. Materials used on MBE
III-V semiconductors offer high
electron mobility and a direct high
band gap.
II-VI semiconductors exhibit direct
large band gaps , but have some
problems with conductivity.
IV – VI Semiconductors also offer a
narrow band gap.
17. Clean surfaces.
Monitoring in situ.
Independent vaporization of each
material.
Multiple sources are used to grow
alloy films and heterostructures.
Deposition is controlled at
submonolayer level.
Extremely flexible technique since
growth parameters are varied
independently.
Benefits/Problems of MBE
Very low deposition rates: 1um –
100nm per hour are used.
High equipment cost and long set
up time.
Extreme Flexibility (uncontrolled
flexibility = chaos!).
Many Boring Evenings!
Mostly Broken Equipment!
Mega-Buck Evaporation!
19. Applications
The driving force today is the fabrication of advanced electronic and
optoelectronic devices.
Transistors (HEMT,HBT):
Microwave devices (IMPATT)
Optoelectronic devices (MQW) laser
21. Very well controlled and clean result.
High equipment cost and long setup time
In situ monitoring
High Speed electronic and optoelectronic applications
III-V semiconductors as GaAs are the most common used in Electronic
and OptoElectronics devices.
Conclusions