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EXPERIMENTAL DETAILS
5 pair
Ti/Al
transparent current spreading layer
Mg-doped p-GaN 200nm
Δ-doped GaN barrier 16nm
InGaN well 2nm
Δ-doped GaN barrier 16nm
n-GaN 2um
u-GaN 2um
LT GaN buffer 25nm
sapphire
low temperature of 800 °C
Ni/Au
temperature at 1040°C
temperature at 550°C
temperature of 1050 °C
FIG. 1. Schematic diagram of a 385-nm UV LED
structure with Si delta doping in the barrier of the
MQWs.
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Ec
Ev
8-nm-thick undoped GaN
Si delta-doped
Ec
8-nm-thick undoped GaN
well
8-nm-thick undoped GaN
barrier
Si delta-doped
Ev
8-nm-thick undoped GaN
Fig.2.GaN barrier layer is as follows: An 8-nm-thick undoped GaN
layer was initially grown, and the gas supply of trimethylgallium was
then stopped for 10 s on top of the GaN layer while flow of the
ammonia was maintained. After this pre-deltadoping purge step, the
deposition of SiH4 was followed for several tens of seconds under
the Ga free condition for Si delta doping. An 8-nm-thick undoped
GaN capping layer was then deposited.
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To confirm the formation of a delta-doped layer in the
GaN barrier layer
 C–V measurements were carried out on the Si delta-doped barrier layer.
 When the SiH4 flow rate was increased from 2 to 10 SCCM , the
ionized impurity concentration in the delta-doping layer was increased
from 3 × 1019 𝑡𝑜 4.5 × 1019 /𝑐𝑚3 .
(1) doping concentration in our sample is already high enough to be
saturated since the growth temperature of our samples is typically
lower by 200 °C
(2) The compensation of the donor by the amphoteric behavior of silicon.
 The full width at half maximum in the doping profile was around 3–5
nm.
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