Long wavelength bulk GaInNAs p−i−n photodiodes lattice matched to GaAs

Abstract

We report bulk GaInNAs p − i − n photodiodes lattice-matched to GaAs substrates, grown by solid source molecular beam epitaxy with photoresponses out to ϳ1.3 m. The as-grown samples were characterized optically, structurally, and electrically. A low background doping concentration in the range of 10 14 -10 15 cm −3 was obtained in the samples. One of the samples with a 0.5 m thick GaInNAs absorbing layer gave a responsivity of 0.11 A/W for a band edge of 1.28 m at reverse bias of 2 V.

Improved Optoelectronic Properties of Rapid Thermally Annealed Dilute Nitride GaInNAs Photodetectors

“…Although the growth conditions were broadly similar to those reported in Ref. 5, the growth temperature of the GaInNAs epilayer was modified slightly to 420°C instead of 450°C in order to maintain mirror-like surface morphology. The growth parameters for the GaInNAs epilayer were the same as previously reported, with a growth rate of about 0.56 lm/h, RF power of 180 W, and N 2 flow rate of 0.2 sccm.…”

“…The GaAs cladding layers were grown at 590°C at a rate of 0.5 lm/h, similar to the previous growth conditions. 5 The unintentional background doping in the i-region was found by capacitance-voltage (C-V) measurements to be at mid 10 16 cm À3 , much higher than the $10 14 cm À3 achieved previously. 5 This suggests that the growth conditions were not optimal, possibly due to problems with the N 2 plasma source or incorporation of unwanted impurities.…”

“…5 The structure contains nominal In and N compositions of 10% and 3.8%, respectively, and layer structure as shown in Table I, which is similar to that of the optimally grown Ga 0.90 In 0.10-N 0.038 As 0.962 sample (''wafer C'') reported in Ref. 5, except with an intrinsic-region (or i-region) thickness of 1 lm instead of 0.4 lm. The n + AlAs layer below the n + GaAs cladding was designed to be an etch-stop layer.…”

“…15 It was reported in our previous work that GaInNAs p-i-n diodes lattice matched to GaAs with low background doping concentration, low dark currents, and a photoresponse cutoff wavelength up to 1.28 lm could be achieved without postgrowth annealing. 5 However, recently a series of wafers grown under similar conditions were found to produce weak PL and devices with high dark currents and high background doping concentration (mid 10 16 cm À3 ). Significant improvement in PL and device performance was observed following a short thermal treatment by rapid thermal annealing (RTA).…”

“…Since its proposal by Kondow et al 1 as a material for near-infrared lasers, widespread interest followed and expanded into other optoelectronic devices including high-efficiency multijunction solar cells 2,3 and near-infrared photodetectors. 4,5 Unfortunately, growth of high-quality GaInNAs epilayers remains a challenge due to defects and other problems associated with nitrogen incorporation, the low growth temperature, and/or ion damage from the radiofrequency (RF) plasma source. 6 Many material quality and device performance issues that plagued the early development of Ga(In)NAs, such as poor photoluminescence (PL) efficiency, 7 high dark currents, 8 and short minority carrier diffusion lengths, 9 still persist today.…”