Search results
Results from the WOW.Com Content Network
A homojunction is a semiconductor interface that occurs between layers of similar semiconductor material; [1] these materials have equal band gaps but typically have different doping. In most practical cases a homojunction occurs at the interface between an n-type ( donor doped) and p-type ( acceptor doped) semiconductor such as silicon , this ...
A laser diode (LD, also injection laser diode or ILD or semiconductor laser or diode laser) is a semiconductor device similar to a light-emitting diode in which a diode pumped directly with electrical current can create lasing conditions at the diode's junction.
Light is generated in a semiconductor laser by radiative recombination of electrons and holes. In order to generate more light by stimulated emission than is lost by absorption, the system's population density has to be inverted, see the article on lasers. A laser is, thus, always a high carrier density system that entails many-body interactions.
These semiconducting materials have unequal band gaps as opposed to a homojunction. It is often advantageous to engineer the electronic energy bands in many solid-state device applications, including semiconductor lasers, solar cells and transistors.
The feedback mechanism is suppressed to prevent the device to go into a saturated emission mode. At the heterojunction (extrinsic semiconductor layers used as interfaces between two homojunction materials), the guiding principle for optical power is total internal reflection, which guides the power out at the emitting facet of LED via a path that is parallel to the junction.
The height of the lines and bars gives an indication of the maximal power/pulse energy commercially available, while the color codifies the type of laser material (see the figure description for details). Most of the data comes from Weber's book Handbook of laser wavelengths, [1] with newer data in particular for the semiconductor lasers.
A PIN-type photo detector is formed by the base-collector-subcollector layers. The bandgap of InGaAs works well for detecting 1550 nm-wavelength infrared laser signals used in optical communication systems. Biasing the HBT to obtain an active device, a photo transistor with high internal gain is obtained.
Semiconductors, a type of solid, crystal with uniform dopant distribution or material with differing dopant levels in which the movement of electrons can cause laser action. Semiconductor lasers are typically very small, and can be pumped with a simple electric current, enabling them to be used in consumer devices such as compact disc players