Silicon bandgap temperature sensor

About: Silicon bandgap temperature sensor is a research topic. Over the lifetime, 1183 publications have been published within this topic receiving 27132 citations.

Direct observation of a widely tunable bandgap in bilayer graphene

Abstract: The electronic bandgap is an intrinsic property of semiconductors and insulators that largely determines their transport and optical properties. As such, it has a central role in modern device physics and technology and governs the operation of semiconductor devices such as p-n junctions, transistors, photodiodes and lasers. A tunable bandgap would be highly desirable because it would allow great flexibility in design and optimization of such devices, in particular if it could be tuned by applying a variable external electric field. However, in conventional materials, the bandgap is fixed by their crystalline structure, preventing such bandgap control. Here we demonstrate the realization of a widely tunable electronic bandgap in electrically gated bilayer graphene. Using a dual-gate bilayer graphene field-effect transistor (FET) and infrared microspectroscopy, we demonstrate a gate-controlled, continuously tunable bandgap of up to 250 meV. Our technique avoids uncontrolled chemical doping and provides direct evidence of a widely tunable bandgap-spanning a spectral range from zero to mid-infrared-that has eluded previous attempts. Combined with the remarkable electrical transport properties of such systems, this electrostatic bandgap control suggests novel nanoelectronic and nanophotonic device applications based on graphene.

A continuous-wave Raman silicon laser

Abstract: Achieving optical gain and/or lasing in silicon has been one of the most challenging goals in silicon-based photonics because bulk silicon is an indirect bandgap semiconductor and therefore has a very low light emission efficiency. Recently, stimulated Raman scattering has been used to demonstrate light amplification and lasing in silicon. However, because of the nonlinear optical loss associated with two-photon absorption (TPA)-induced free carrier absorption (FCA), until now lasing has been limited to pulsed operation. Here we demonstrate a continuous-wave silicon Raman laser. Specifically, we show that TPA-induced FCA in silicon can be significantly reduced by introducing a reverse-biased p-i-n diode embedded in a silicon waveguide. The laser cavity is formed by coating the facets of the silicon waveguide with multilayer dielectric films. We have demonstrated stable single mode laser output with side-mode suppression of over 55 dB and linewidth of less than 80 MHz. The lasing threshold depends on the p-i-n reverse bias voltage and the laser wavelength can be tuned by adjusting the wavelength of the pump laser. The demonstration of a continuous-wave silicon laser represents a significant milestone for silicon-based optoelectronic devices.

High-temperature electronics - a role for wide bandgap semiconductors?

Abstract: The fact that wide bandgap semiconductors are capable of electronic functionality at much higher temperatures than silicon has partially fueled their development, particularly in the case of SiC. It appears unlikely that wide bandgap semiconductor devices will find much use in low-power transistor applications until the ambient temperature exceeds approximately 300/spl deg/C, as commercially available silicon and silicon-on-insulator technologies are already satisfying requirements for digital and analog VLSI in this temperature range. However practical operation of silicon power devices at ambient temperatures above 200/spl deg/C appears problematic, as self-heating at higher power levels results in high internal junction temperatures and leakages. Thus, most electronic subsystems that simultaneously require high-temperature and high-power operation will necessarily be realized using wide bandgap devices, once they become widely available. Technological challenges impeding the realization of beneficial wide bandgap high ambient temperature electronics, including material growth, contacts, and packaging, are briefly discussed.

An all-silicon Raman laser

Abstract: With the growing use of optoelectronics in information technology, manipulating light is almost as important as manipulating electrons. Unfortunately silicon, workhorse of modern microelectronics, is next to useless in optical applications. There has been a massive effort to overcome silicon's inadequacies, and ways of coaxing silicon to handle light are under development but a key component — the laser — has been problematic. Last year a silicon laser was produced, but it involved metres of optical fibre. Now workers in Intel's research labs have come up with an all-silicon laser on a single chip. The device is compact and readily integrated with other silicon components. The possibility of light generation and/or amplification in silicon has attracted a great deal of attention1 for silicon-based optoelectronic applications owing to the potential for forming inexpensive, monolithic integrated optical components. Because of its indirect bandgap, bulk silicon shows very inefficient band-to-band radiative electron–hole recombination. Light emission in silicon has thus focused on the use of silicon engineered materials such as nanocrystals2,3,4,5, Si/SiO2 superlattices6, erbium-doped silicon-rich oxides7,8,9,10, surface-textured bulk silicon11 and Si/SiGe quantum cascade structures12. Stimulated Raman scattering (SRS) has recently been demonstrated as a mechanism to generate optical gain in planar silicon waveguide structures13,14,15,16,17,18,19,20,21. In fact, net optical gain in the range 2–11 dB due to SRS has been reported in centimetre-sized silicon waveguides using pulsed pumping18,19,20,21. Recently, a lasing experiment involving silicon as the gain medium by way of SRS was reported, where the ring laser cavity was formed by an 8-m-long optical fibre22. Here we report the experimental demonstration of Raman lasing in a compact, all-silicon, waveguide cavity on a single silicon chip. This demonstration represents an important step towards producing practical continuous-wave optical amplifiers and lasers that could be integrated with other optoelectronic components onto CMOS-compatible silicon chips.

Review of Silicon Carbide Power Devices and Their Applications

Abstract: Silicon carbide (SiC) power devices have been investigated extensively in the past two decades, and there are many devices commercially available now. Owing to the intrinsic material advantages of SiC over silicon (Si), SiC power devices can operate at higher voltage, higher switching frequency, and higher temperature. This paper reviews the technology progress of SiC power devices and their emerging applications. The design challenges and future trends are summarized at the end of the paper.