Light Emitting Transistor and Laser Revised.Indd

Office of Technology Management

UNIVERSITY OF ILLINOIS AT URBANA - CHAMPAIGN

Light Emitting Transistor and Laser This invention is the world’s ﬁ rst light emitting transistor. The HBLET extends the capabilities of light-emitting diodes and could make this transistor the fundamental element in electronics and optoelectronics. Photonics, optics & lasers

Speed These transistors produce infrared light in phase with their base current, allowing it applications

ts to attain a switching speed superior to light ﬁ emitting diodes (LEDs). Electronics

Controlled light emission Optoelectronics Light intensity can be controlled by varying the base current. Displays

bene Simultaneous control of optical and electrical outputs The addition of a third port allows greater control. Tech No. TF04036 Utilizes base current U.S. Patent applications pending Once considered wasteful, the base current is used to create light. Investigators Milton Feng & Nick Holonyak www.ece.uiuc.edu Tech Manager Steven Wille Phone: 217.244.5956 Email: [email protected]

For more information about the Ofﬁ ce of Technology Management please call us at 217.333.7862 or visit our website at: www.otm.uiuc.edu

In a bipolar device there are two kinds of injected These transistors are made with indium gallium carriers, negatively charged electrons and phosphide and gallium arsenide, unlike traditional positively charged holes. Some of these carriers, transistors which have been built from silicon and for example, a transistor, recombine rapidly, germanium. The recombination process in indium supported by a base current essential for normal gallium phosphide and gallium arsenide materials transistor function. create infrared photons, the “light” in the light emitting transistor. This contributes to the device’s In the past, this base current has been regarded ability to operate as both a laser and a transistor. as a waste current that generates unwanted heat.

Photonics, optics & lasers However, this technology shows the base current The existence of a third port (the photon output) creates light that can be modulated at transistor can interconnect optical and electric signals for speed. display or communication purposes. Additionally, electrical and optical qualities are increased by This recombination process is the same (but the incorporation of quantum wells into the active enhanced by carrier transport) as the one used in region of the transistors. LEDs to produce visible, rather than infrared, light. The transistor laser produces infrared radiation in The transistor laser has a unique capability in signal phase with its base current, so it can be modulated processing and electronic-photonic integrated at a switching speed impossible to attain with an circuits. LED. The switching speed obtained is fast enough to operate in ﬁ ber optic networks, as well as other applications.

For more information about the Ofﬁ ce of Technology Management please call us at 217.333.7862 or visit our website at: www.otm.uiuc.edu