Multiple functional UV devices based on III-Nitride quantum wells for biological warfare agent detection

Abstract

We have demonstrated surface normal detecting/filtering/emitting multiple functional ultraviolet (UV) optoelectronic devices based on InGaN/GaN, InGaN/AlGaN and Al x Ga 1-x N/Al y Ga 1-y N multiple quantum well (MQW) structures with operation wavelengths ranging from 270 nm to 450 nm. Utilizing MQW structure as device active layer offers a flexibility to tune its long cut-off wavelength in a wide UV range from solar-blind to visible by adjusting the well width, well composition and barrier height. Similarly, its short cut-off wavelength can be adjusted by using a GaN or AlGaN block layer on a sapphire substrate when the device is illuminated from its backside, which further provides an optical filtering effect. When a current injects into the device under forward bias the device acts as an UV light emitter, whereas the device performs as a typical photodetector under reverse biases. With applying an alternating external bias the device might be used as electroabsorption modulator due to quantum confined Stark effect. In present work fabricated devices have been characterized by transmission/absorption spectra, photoresponsivity, electroluminescence, and photoluminescence measurements under various forward and reverse biases. The piezoelectric effect, alloy broadening and Stokes shift between the emission and absorption spectra in different InGaN-and AlGaN-based QW structures have been investigated and compared. Possibilities of monolithic or hybrid integration using such multiple functional devices for biological warfare agents sensing application have also be discussed.

A TCAD-based modeling of GaN/InGaN/Si solar cells

“…Rapid progress in III-N (nitride) material growth and device fabrication has enabled demonstration of UV light-emitting diodes with emission from 200 nm to 400 nm [1][2][3] and highefficiency visible-blind and solar-blind photodetectors [4,5] for commercial and military applications. Since the application area of the III-nitride devices is steadily spreading, several new commercial devices such as UV-LED and high-frequency high-power electronic devices begin to be available.…”

Micro-optical elements functioning in non-visible spectral range

“…In this section we describe and discuss two MOE integration examples onto the optoelectronic devices using the microlens concept, one device is the quantum dot infrared photodetector (QDIP) [8], and another one is the GaN-based quantum well UV detector/emitter dual functional device [9]. The substrate of the QDIP is GaAs, its thickness is 350 µm or 525 µm as using 2'' or 4'' substrate, respectively.…”

Sandwich method to grow high quality AlN by MOCVD

“…III-nitride based materials have attracted attention due to their excellent physical, electrical, and optical properties, and their high chemical and thermal stability as compared to traditional III-V semiconductors. The UV capabilities of III-nitride materials are of special interest for civilian applications such as air and water sterilization, efficient white lighting, high density optical data storage and military applications such as biological agent detection and non-line-of-sight communication [1][2][3][4], etc.…”