The glass-forming region was determined for the system Ge-Bi-Se; 13 at.% Bi was found to be incorporated at its maximum content into glasses, the Ge content of which was 20 at.%. Electrical resistivity, thermoelectric power, and optical absorption coefficient were measured mainly on a series of Ge20BixSe80−x glasses (x=0 –13). The resistivity decreased by about four orders of magnitude between x=9 and 10, and remained almost constant for x?10. The thermoelectric measurement showed the change of conduction type from p to n, accompanied by the above-mentioned abrupt decrease of resistivity. In n-type glasses, hopping conduction in the tail of localized states was proposed in parallel with conduction in extended states. The optical band gap was very slightly changed with the incorporation of more than 2.5 at.% Bi, in contrast to the remarkable decrease in the activation energy for conduction between x=9 and 10. The discussion based on the concentration of covalent bonds formed in the glasses led to the conclusion that the formation of a fairly large number of Bi-Se bonds and the disappearance of Se-Se bonds near x=10 were closely related to the composition dependence of the electrical and optical properties of the glasses in the present system.
Novel devices to serve the needs of ubiquitous network require powerful input-output terminals with exceptional characteristics. In response to these requirements, we have developed high performance TFTs and System LCD using CG Silicon® technology. In addition, we have demonstrated advanced system integration technology for mobile application such as sensors, the fusion of audio with visual and fine picture quality with good image control. And we have been developing Flexible Displays, and a new Reflective LCD technology for achieving super low power consumption.
Using data retention circuits that include crystalline oxide semiconductor transistors as backup circuits for power gating, a processor system can reduce standby leakage current significantly. This is effective in the Internet of Things (IoT) applications that require standby power reduction. The crystalline oxide semiconductor transistor can constitute a nonvolatile data retention circuit easily because it exhibits significantly lower off-state current than a silicon transistor and is highly compatible with a CMOS logic circuit. The backup circuit can achieve 2-clock-cycle data backup and 4-clock-cycle data restore; thus, the processor system can efficiently perform temporally fine-grained power gating and can achieve longer standby times. Furthermore, area overheads due to the backup circuits are kept very small because the crystalline oxide semiconductor transistors are stacked on silicon transistors.
Using a pulse laser holography method, it is possible to record moving objects in three dimensions. Furthermore when a double pulse light source is obtained, it is possible to perform the double pulse holography, and various high speed phenomena can be investigated. We could get a double pulse from doubly Q-switched ruby laser and made two kinds of double pulse holograms, and showed the utility of double pulse holography method.
TFT-LCD technology has been under development for both TVs and mobile applications. For LCD-TVs, large size substrate handling technology plays a critical role in fabrication. In the mobile arena, smart and stylish information tools are strongly desired which incorporate the features of high usability, low power consumption, compactness (thin and light weight), high resolution and good image quality. CG Silicon® Technology* has been developed to realize high performance TFTs and enable new technologies such as LCDs with integrated display drivers and sensor functionality.
The keywords for the ubiquitous network and high-information-content era are “information” and “audio-visual”. Novel devices to serve the needs of ubiquitous network require powerful input-output terminals with exceptional characteristics. In response to these requirements, we have developed high performance TFTs and “System LCD” using CG Silicon® technology. In addition, we have demonstrated advanced system integration technology for mobile application such as sensors, the fusion of “audio” with “visual” and fine picture quality with good image control. For future, ubiquitous information tools, we are developing super-advanced poly-Si TFT devices capable of frequencies of over 1GHz on glass substrate.
We demonstrate that the two-dimensional electron gas concentration in an InAs/AlGaSb heterostructure can be greatly increased by introducing a Si planar-doped ultrathin InAs quantum well (QW) sandwiched between AlSb barriers as an additional electron supplying layer in a well controlled fashion. With the Si planar-doped QW formed 8 nm below the channel layer, the sheet electron concentration increased up to 4.5×10 12 cm -2 with an electron mobility of 4×10 4 cm 2 / Vs at 77 K. Shubnikov-de Haas measurements revealed that only two subbands are occupied, even for heavily doped samples. The energy separation between the first and the second subbands is as large as 100 meV, indicating a strong electron confinement in the selectively doped InAs/AlGaSb heterostructures.
