Group III-nitride semiconductor Schottky barrier photodiodes for radiometric use in the UV and VUV regions

Abstract

We have developed Schottky barrier photodiodes of AlN, AlxGa1−xN, GaN and InyGa1−yN grown on n-SiC. Spectral responsivity measurements demonstrate that the devices fabricated have sharp cut-offs with a rejection ratio of over 3 decades and the cut-off wavelength can be varied by changing the alloy or the composition of the alloys. The internal quantum efficiency of an Al0.19Ga0.81N photodiode is estimated to reach 64% around 300 nm. It is also confirmed that the photodiodes do not notably degrade in responsivity to the UV radiant exposure of 5 kJ cm−2 in contrast to Si photodiodes. Characterization on uniformity, temperature dependence and angular response is also conducted and gives satisfactory results for all items. In conclusion, the Schottky barrier photodiodes of AlN, AlxGa1−xN, GaN and InyGa1−yN work properly as expected and look very promising for precise measurements in the VUV and UV regions.

Spectral Properties of Semiconductor Photodiodes

“…A number of developments for better stability and solar-blindness have been reported by using various kind of wide bandgap materials like diamond (Saito, T. et al, 2005a;Saito, T. et al, 2005b;Saito, T. et al, 2006), AlN, AlGaN, InGaN etc. (Saito, T. et al, 2009a;Saito, T. et al, 2009b). To check the validity of the calculation model described in Chapter 3, a number of comparisons have been conducted in the wide wavelength range from 10 nm to 1000 nm.…”

UV/VUV photodetectors using group III‐nitride semiconductors

“…Therefore, as the temperature increases, the cut-off wavelength shifts to a longer wavelength, and this results in an increase in responsivity at a wavelength near the cutoff wavelength where the spectral responsivity varies steeply with the wavelength. 4.4 Stability to UV radiation Temporal stability to UV radiation was tested for Al 0.52 Ga 0.48 N, GaN and In 0.05 Ga 0.95 N Schottky barrier photodiodes and Si photodiodes using a low-pressure mercury lamp in nitrogen atmosphere [14]. The experimental results show that photocurrents of all the nitride photodiodes are constant within the experimental uncertainty to the UV radiant exposure of 5.0 kJ/cm 2 while silicon photodiodes exhibit rapid degradation of 70% with exposure of 500 kJ/cm 2 .…”

Влияние температуры на характеристики 4H-SiC-фотоприемника

“…Детекторы на основе таких материалов чувствительны к видимому и инфракрасному (ИК) излучениям, что требует применения УФ фильтров, резко снижающих квантовую эффективность приборов [1,3]. Для создания " видимо-слепых" фотоприемников, не требующих применения светофильтров, перспективны более широкозонные полупроводники -GaN, AlN и твердые растворы на их основе, алмазы [2,[4][5][6]. Однако ввиду низких значений теплопроводности и значительных темновых токов при нагреве такие детекторы требуют применения принудительного охлаждения, что существенно увеличивает габариты, вес аппаратуры и энергозатраты [1,7,8].…”