Mechanisms of recombination in GaN photodetectors

Abstract

Steady-state and transient responses of a nonintentionally doped GaN photodetector are investigated. The kinetics of the photoresponse demonstrate the existence of deep levels in the gap, acting as recombination centers with an acceptor character. The photoresponse displays two competing processes: a bimolecular recombination, dominating at high optical power range, and a monomolecular recombination involving long response times. The observed persistent photoconductivity and the huge photoconductive gain are due to the small electron capture cross section and a much faster hole capture rate.

Characterization and Modeling of Photoconductive GaN Ultraviolet Detectors

“…Therefore, there is a dependence of photoconductive gain on frequency which prevents obtaining information about the gain mechanism from AC measurements. These results explain the data reported by Kung [7] and by Binet [9] on similar GaN devices.…”

“…Some of the characteristics of GaN photoconductors have been reported. There is a general agreement on the presence of an abnormally high responsivity [5] [6] [9] and persistent photoconductivity [7] [10] [11], which have been tentatively attributed either to deep levels [9] or to Mg-doping related centers [8]. A frequency dependence of the responsivity has also been detected [7] [11].…”

“…Photocoductive GaN detectors have early attracted a significant interest [5] [6] [7] [8] [9]. For their simplicity, they are candidates as low cost UV detectors in consumer and environmental applications.…”

Ultrahigh-gain single SnO2 nanowire photodetectors made with ferromagnetic nickel electrodes

“…[26][27][28] Therefore, it is very desirable to understand the mechanism enabling the ultrahigh PC gain obtained here. According to the reports by Binet et al 29 and Muñoz et al, 30 the relationship between the PC gain and the illumination intensity is very informative when considering the underlying mechanism. As shown in Figure 3b, the gain plot (logarithmic) versus intensity shows that there is a turning point in each curve and that the value of the light intensity for the turning point to occur increases with increasing magnetization of the ferromagnetic electrodes.…”

Quantum structures for multiband photon detection

“…A GaN/AlGaN UV detector can detect UV radiation by interband absorption in the AlGaN barrier layer. UV detectors have already been demonstrated by several groups [32][33][34] using GaN/AlGaN system. Intraband transitions giving rise to IR absorption in GaN/AlGaN is similar to that in GaAs/AlGaAs HEIWIP detectors [35].…”