DURIP: Semiautomated Optoelectronics Characterization System for Deep-Ultraviolet Photodetectors and Solar Cells
Abstract
It is well known that wide band gap semiconductor materials and devices are becoming an ever-increasing component in both electronic and photonic device applications. In order to understand the importance of this DURIP being awarded to UCD, a brief summary of the origin of early photonic device breakthroughs based in wide-gap semiconductors is useful. For this discussion, we arbitrarily define wide-gap materials as those with band gaps > 2.2 eV, e.g., just below the band gap of GaP. The wide-gap photonic device movement had a false start with the achievement of room temperature, cw, green lasers, made with heterojunctions of ZnSe (BG = 2.7 eV). This breakthrough resulted from a previous breakthrough of being able to p-dope ZnSe. However, stimulated emission in the lasing region of ZnSe laser diodes caused rapid degradation of the laser. As a result, interest in the ZnSe laser breakthrough was short lived. Since prior to the p-doped ZnSe breakthrough, most II-VI textbooks taught that achieving p-doping in wide-gap semiconductors would be problematic, owing to the equilibrium doping compensation physics, which can limit p-doping of wide-gap materials. Thus, in itself, the achievement of p-doped ZnSe result inspired renewed interest in the possibility in achieving p-n junctions in other wide-gap materials. Wide-gap materials and device research escalated when Shuji Nakamura fabricated high efficiency blue emitting LEDs using double heterojunctions of GaN/InGaN/GaN. After that, GaN produced blue and UV lasers. This breakthrough, as for the ZnSe laser, happened when Nakamura and his colleagues figured out how to dope GaN p-type. As a result of fabricating efficient blue-UV GaN LEDs, they became the LED optical driver of the of the now commercially ubiquitous white LEDs. As a result, Nakamura and colleagues shared the 2014 Nobel Prize in physics.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 31, 2020
- Accession Number
- AD1225299
Entities
People
- Jerry Woodall
Organizations
- University of California