A solid-state substance that can be electrically altered. Certain elements in nature, such as silicon, perform like semiconductors when chemically combined with other elements. A semiconductor is halfway between a conductor and an insulator. When charged with electricity or light, semiconductors change their state from nonconductive to conductive or vice versa. The most significant semiconductor is the transistor, which is simply an on / off switch.

The transistor is a semiconductor device that can be used for amplification, switching, voltage stabilization, signal modulation and many other functions. It allows a variable current, from an external source, to flow between two of its terminals depending on the smaller voltage or current applied to a third terminal. Transistors are made either as separate components or as part of an integrated circuit. Millions of individual transistors are known as discretes.

A monolithic integrated circuit (also known as IC, microchip, silicon chip, computer chip or chip) is a miniaturized electronic circuit (consisting mainly of semiconductor devices, as well as passive components) which has been manufactured in the surface of a thin substrate of semiconductor material.

A hybrid integrated circuit is a miniaturized electronic circuit constructed of individual semiconductor devices, as well as passive components, bonded to a substrate or circuit board.

A discrete device is an electronic component with just one circuit element. The term is used to distinguish the component from integrated circuits and hybrid circuits, which are built from several circuit elements in one package. It typically refers to semiconductor devices.

Wafer Fabrication is a procedure comprised of many repeated sequential processes to produce complete electrical or photonic circuits. Examples include production of radio frequency (RF) amplifiers, LEDs, optical computer components, and CPUs for computers. Wafer fabrication is used to build components with the necessary electrical structures.

Wafer testing or wafer probing is the process of testing each wafer before packaging using very expensive automated test equipment (ATE).

The wafer is then cut into small rectangles called dice. Each good die is then connected into a package using aluminum (or gold) wires which are welded to pads, usually found around the edge of the die. After packaging, the devices go through final test on the same or similar ATE used during wafer probing. Test cost can account for over 25% of the cost of fabrication on lower cost products, but can be negligible on low yielding, larger, and/or higher cost devices.

The first integrated circuits contained only a few transistors. Called "Small-Scale Integration" (SSI), they used circuits containing transistors numbering in the tens.

The next step in the development of integrated circuits, taken in the late 1960s, introduced devices which contained hundreds of transistors on each chip, called "Medium-Scale Integration" (MSI).

"Large-Scale Integration" (LSI) in the mid 1970s produced tens of thousands of transistors per chip. They were attractive economically because while they cost little more to produce than SSI devices, they allowed more complex systems to be produced using smaller circuit boards, less assembly work (because of fewer separate components), and a number of other advantages.

Further development led to LSI circuits being produced in large quantities for computer main memories and pocket calculators.

The final step in the development process, starting in the 1980s and continuing on, was "Very Large-Scale Integration" (VLSI), with hundreds of thousands of transistors, and beyond (well past several million in the latest stages).

The growth of complexity of integrated circuits follows a trend called "Moore's Law", first observed by Gordon Moore of Intel. Moore's Law in its modern interpretation states that the number of transistors in an integrated circuit doubles every two years. By the year 2000 the largest integrated circuits contained hundreds of millions of transistors.

Rock's Law, named for Arthur Rock, says that the cost of a semiconductor chip fabrication plant doubles every four years. As of 2003, the price had already reached about 3 billion US dollars.

Rock's Law can be seen as the economic flipside to Moore's Law; the latter is a direct consequence of the ongoing growth of the capital-intensive semiconductor industry-innovative and popular products mean more profits, meaning more capital available to invest in ever higher levels of large-scale integration, which in turn leads to creation of even more innovative products.

The semiconductor industry has always been extremely capital-intensive, with very low unit manufacturing costs. Thus, the ultimate limits to growth of the industry will constrain the maximum amount of capital that can be invested in new products; at some point, Rock's Law will collide with Moore's Law.

In this approach, components traditionally manufactured as separate chips to be wired together on a printed circuit board are designed to occupy a single chip that contains memory, microprocessor(s), peripheral interfaces, Input/Output logic control, data converters, and other components, together composing the whole electronic system.

In microelectronics, a foundry refers to a factory where devices such as integrated circuits are manufactured.

A fabless semiconductor company specializes in the design and sale of hardware devices implemented on semiconductor chips. It achieves an advantage by outsourcing the fabrication of the devices to a specialized semiconductor manufacturer called a semiconductor foundry or "fab". The credit for pioneering the fabless concept is given to Bernie Vonderschmitt of Xilinx and Gordon A. Campbell of Chips and Technologies.

A fabless company may concentrate its research and development resources on the end market without being required to invest resources in staying current in semiconductor technology. For this reason they are also known as IP firms, because their primary product consists of licenses in patents, trade secrets, mask works, and other forms of intellectual property.

Merchant foundries only manufacture devices under contract by other companies, without designing them. They are able to find work from the pool of fabless companies and by careful scheduling, pricing and contracting remain at full utilization.

An integrated device manufacturer (IDM) is a semiconductor company which designs, manufactures, and sells integrated circuit (IC) products.

An original equipment manufacturer (frequently abbreviated "OEM") is a company that builds products or components which are used in products sold by another company (often called a value-added reseller, or VAR). An OEM will typically build to order based on designs of the VAR. For example, a hard drive in a computer system may be manufactured by a corporation separate from the company that markets and sells the computer, or a loudspeaker in a stereo system made by a company that specializes in audio manufacturing.

Some OEMs have also taken on a larger role in the design of the product they are manufacturing. The term Original Design Manufacturer (ODM) is used to describe companies that design and manufacture a product that is then sold under other brand names.

An embedded system is a special-purpose system in which the computer is completely encapsulated by the device it controls. Unlike a general-purpose computer, such as a personal computer, an embedded system performs pre-defined tasks, usually with very specific requirements. Example: Routers, ATMs, cellular phones.

Electronic design automation (EDA) is the category of tools for designing and producing electronic systems ranging from printed circuit boards (PCBs) to integrated circuits. This is sometimes referred to as ECAD (electronic computer-aided design) or just CAD.

A microcontroller (or MCU) is a computer-on-a-chip used to control electronic devices. It is a type of microprocessor emphasizing self-sufficiency and cost-effectiveness, in contrast to a general-purpose microprocessor (the kind used in a PC). A typical microcontroller contains all the memory and interfaces needed for a simple application, whereas a general purpose microprocessor requires additional chips to provide these functions.

A microprocessor (sometimes abbreviated µP) is a digital electronic component with miniaturized transistors on a single semiconductor integrated circuit (IC). One or more microprocessors typically serve as a central processing unit (CPU) in a computer system or handheld device.

A central processing unit (CPU), or sometimes simply processor, is the component in a digital computer that interprets instructions and processes data contained in computer programs. CPUs provide the fundamental digital computer trait of programmability, and are one of the necessary components found in computers of any era, along with primary storage and input/output facilities. A CPU that is manufactured using integrated circuits is known as a microprocessor. Since the mid-1970s, single-chip microprocessors have almost totally replaced all other types of CPUs, and today the term "CPU" is usually applied to some type of microprocessor.

An application-specific integrated circuit (ASIC) is an integrated circuit (IC) customised for a particular use, rather than intended for general-purpose use. For example, a chip designed solely to run a cell phone is an ASIC. In contrast, the 7400 series and 4000 series integrated circuits are logic building blocks that can be wired together to perform many different applications. Intermediate between ASICs and standard products are application specific standard products (ASSPs).

An analog or analogue signal is any variable signal continuous in both time and amplitude. It differs from a digital signal in that small fluctuations in the signal are meaningful.

30. What is photovoltaic (PV)?

PV is a basic type of solar electric technology. The photovoltaic (PV) process converts sunlight, the most abundant energy source on the planet directly into electricity. The equipment required for this process has no moving parts and as a result requires minimal maintenance. In addition, the electricity is generated with no emissions and no noise.

A PV cell consists of two or more thin layers of semiconducting material, most commonly silicon. When the cell is exposed to light, electrical charges are generated and this can be conducted away by metal contacts as direct current (DC).

The electrical output from a single cell is small, therefore multiple cells are connected together to provide a more useful output. Cells connected in this way are encapsulated (usually behind glass) to form a weatherproof module or panel.

Multiple modules can likewise be connected together in order to provide sufficient power for common electrical appliances.

31. What is the history of PV technology?

32. What is thin film technology?

33. What types of materials are used in making a photovoltaic cell?

34. Does PV technology need bright sunshine to work properly?

35. What applications are there for PV?

PV technology has many applications, both for stand-alone systems and for integration onto buildings. PV may be used in applications such as monitoring stations, radio repeater stations, telephone kiosks and street lighting to name just a few examples. There is also a substantial market for PV technology in the leisure industry, with battery chargers for boats and caravans, as well as for powering garden equipment such as solar fountains.

In more recent years, PV has become more widely used in urban areas, where it can be integrated into new buildings or mounted onto existing buildings. This is a rapidly growing market. PV technology is ideally suited to the urban environment, providing pollution and noise free electricity without using extra space.

36. How long will a system last?

37. What is the current market for solar-cell/photovoltaic (PV) manufacturing sector?