The effect of surface recombination on current in AlxGa1−xAs heterojunctions

Abstract

Articles you may be interested inInfluence of structural defects on carrier recombination and current gain in an InGaAs/AlGaAs/GaAs heterojunction phototransistor Emitter composition and geometry related surface recombination current of AlGaAs/GaAs heterojunction bipolar transistors Mesa surface recombination current in AlGaAs/GaAs heterojunction bipolar transistors with an emitter-base-emitter structure Effect of oxygenimplant isolation on the recombination leakage current of np + AlGaAs graded heterojunction diodes Appl.We show that the 2kT current in double-heterostructure AlxGal_xAs p-n junctions is primarily due to surface recombination at the junction perimeter. The rate of surface recombination is evaluated by means of two luminescence experiments. Both experiments provide evidence that the rate of surface recombination increases with bias as exp( e V /2 kT) and has the correct magnitude to account for the measured I· V curves. It is shown theoretically that recombination at a depleted surface is proportional to exp( e V /2 kT) at high bias. The 2 kT behavior is a consequence of the nearly constant ratio of electron and hole densities at the surface. The nearly constant ratio is needed to maintain equality of surface and surface depletion layer charge. p -n junction perimeters of cleaved, etched, and proton-bombarded interfaces are evaluated and found to have similar rates of non radiative recombination with the rate of surface recombination given by R = so(np)1I2, where So is approximately 4X 10 5 cm/sec.

Degradation mechanism analysis in temperature stress tests on III–V ultra-high concentrator solar cells using a 3D distributed model

“…The parameters J 0 2PER and J 02 both have an effect at low voltages; however, several studies in GaAs [16][17][18][19] show that the amplitude of the recombination current with ideality factor n = 2 does not correlate with the area; instead, it correlates with the perimeter. A previous study of degradation in GaAs solar cells revealed changes in the I-V curve at low voltages [8]; consequently, Table 1 Dimensions of the diodes of GaAs used in the study of the recombination current at low voltages.…”

“…From these figures it can be inferred that, as expected, at low voltages the current correlates with the area in agreement with Refs. [16][17][18][19]. Therefore, I 02 is smaller than / 0 2PER.…”

Low effective surface recombination in In(Ga)As/GaAs quantum dot diodes

“…U s is the rate of surface recombination that is proportional to the excess carrier density at the surface, (n(R) À n i ), with a proportionality constant S called the surface recombination velocity. The perimeter recombination current per unit length is found by integrating the surface recombination current density qU s along the direction perpendicular to the junction, over the surface of the active region (or the effective surface diffusion length (L s ), which can be approximated by the active layer thickness for thin (< 0.1 lm) active layers 23 ) where the carrier density at the surface is assumed to be constant along the surface of the active region. Multiplying and dividing by the excess carrier density in the bulk (n(0) À n i ) and using n(0) ¼ n i exp (qV/gkT), the saturation part of the above equation for current density can be written as…”

Quantification of pn-Junction Recombination in Interdigitated Back-Contact Crystalline Silicon Solar Cells

“…In fact, any depleted surface near the bordering pn-junction can lead to severe J 02 -type recombination, due to efficient transport of charge-carriers through the highly doped p-and n-type regions towards this recombination active region. [12] The recombination at the depleted surface near the pn-junction can be about one order of magnitude higher than the recombination current in the depletion region of the junction. [12] Secondly, adjacent highly doped n-and p-type Si regions can induce a tunneling recombination current between the conduction band of n + Si and the valence band of p + Si.…”

“…[12] The recombination at the depleted surface near the pn-junction can be about one order of magnitude higher than the recombination current in the depletion region of the junction. [12] Secondly, adjacent highly doped n-and p-type Si regions can induce a tunneling recombination current between the conduction band of n + Si and the valence band of p + Si.…”