Cover Picture: High quantum efficiency UV detection using a‐Se based photodetector (Phys. Status Solidi RRL 7/2013)

Abstract

Multiplication in the bulk: Photo‐generated elec‐tron–hole pairs are split and accelerated in amorphous selenium bulk, which trigger carrier multiplication generating extra carriers. This carrier multiplication boosts the signal of a photodetector, allowing ultra high‐sensitivity photodetection. The sensitivity of a prototype photodetector, evaluated in terms of external quantum efficiency, is up to 1,000 for ultraviolet light (∼375 nm), which suggests that up to 1,000 carriers are generated per incident photon. In the Letter by Masuzawa et al. (), the physics of the carrier multiplication has been investigated in terms of current–voltage characteristics of the prototype photodetector.

Surface and Optoelectronic Properties of Ultrathin Trigonal Selenium: A Density Functional Theory Study with van der Waals Correction

“…25 In this landscape, techniques utilizing thin films of photosensitive semiconductors offers an opportunity for the development of alternative photon detector designs using new materials such as a-Se. Some experimental work measuring the properties of Se based photon detector in the UV spectrum has taken place, 11,16,17,26,27 but little theoretical work modeling and understanding the optoelectronic properties of Se exist in this frequency range for photons. In particular, systematic studies on Se (both crystalline and amorphous) are not readily available in the literature.…”

“…Amorphous selenium has been the subject of research first for its application in xerographic photocopiers, , then as a medium for direct X-ray imaging, − as well as for applications in composite films used in photocells. − More recently, there has been research into Se’s potential application as a general use photon detector with a potential wide wavelength application from the visible to UV; , see ref for a useful summary.…”

“…Some experimental work measuring the properties of Se based photon detector in the UV spectrum has taken place, ,,,, but little theoretical work modeling and understanding the optoelectronic properties of Se exist in this frequency range for photons. In particular, systematic studies on Se (both crystalline and amorphous) are not readily available in the literature.…”

First principles studies of the surface and opto-electronic properties of ultra-thin t-Se

“…Amorphous selenium has been the subject of research firstly for its application in xerographic photocopiers [5,6], then as a medium for direct X-ray imaging [7,8,9,10], as well as for applications in composite films used in photocells [11,12,13]. More recently research into Se's potential application as a general use photon detector with a potential wide wavelength application from the visible to UV [14,15]; see [16] for a useful summary.…”

“…Some experimental work measuring the properties of Se based photon detector in the UV spectrum has taken place [24,25,9,14,15], but little theoretical work modeling and understanding the opto-electronic properties of Se exists for photons in this frequency range. This work serves as a starting point for such calculations to better understand the properties that a selenium based detector might have for photons in the VUV spectrum.…”