NHK R&D Journal Issue on Image Sensing Devices

March 2019 issue of NHK STRL R&D Journal devoted to imaging devices being developed by the company:

Dark Current Reduction In Crystalline Selenium-Based Stacked-Type CMOS Image Sensors
Shigeyuki IMURA, Keitada MINEO, Kazunori MIYAKAWA, Masakazu NANBA,
Hiroshi OHTAKE And Misao KUBOTA
There is a possibility that highly sensitive imaging devices can be acquired by using avalanches (c-Se)-based stacked-type CMOS image sensors. In this visible region. The increase in the dark current in the low-electric field region (non-avalanche region) has been an issue. In this study, we optimized the growth conditions of the tellurium (Te) nucleation We have fabricated a test device on glass substrates and successfully reduced the dark current to below 100 pA, which is used to prevent the se film from peeling, resulting in a reduction of the dark current in the non-avalanche region. / cm2 (by a factor of 1/100) at a reverse-bias voltage of 15 V.

Improvement in Performance of Photocells Using Organic Photoconductive Films Sandwiched Between Transparent Electrodes
Toshikatsu SAKAI, Tomomi TAKAGI, Yosuke HORI, Takahisa SHIMIZU,
Hiroshi OHTAKE And Satoshi AIHARA
We have developed a superior type of image sensor that has high sensitivity with three sensor elements, each of which is sensitive to only primary colors. , for each R / G / B-sensitive photocell sandwiched between transparent ITO electrodes.

3D Integrated Image Sensors With Pixel-Parallel Signal Processing
Masahide GOTO, Yuki HONDA, Toshihisa WATABE, Kei HAGIWARA,
Masakazu NANBA And Yoshinori IGUCHI
Photodiodes, pulse generation circuits and 16-bit pulse counters are three-dimensional. We studied a three-dimensional integrated image sensor that is capable of pixel-parallel signal processing, there by meeting integrated within each pixel by direct bonding of silicon on insulator (SOI) layers with embedded Au electrodes, which provides in-pixel pulse frequency modulation A / D converters. Pixel-parallel video images with Quarter Video Graphics Array (QVGA) resolution were obtained, demonstrating the feasibility of these next-generation image sensors.

The Japanese version of the Journal has much many papers but it's harder to figure out their technical content.