NADIR. F. HABUBI,, RAID. A. ISMAIL, WALID K. HAMOUDI and HASSAM. R. ABID *
الملخص الانجليزي
n this work, n-ZnO/p-Si heterojunction photodetectors were prepared by drop casting of ZnO
nanoparticles (NPs) on single crystal p-type silicon substrates, followed by (15–60) min; step-
annealing at 600C. Structural, electrical, and optical properties of the ZnO NPs ̄lms deposited on
quartz substrates were studied as a function of annealing time. X-ray di®raction studies showed a
polycrystalline, hexagonal wurtizte nanostructured ZnO with preferential orientation along the
(100) plane. Atomic force microscopy measurements showed an average ZnO grain size within the
range of 75.9 nm–99.9 nm with a corresponding root mean square (RMS) surface roughness between
0.51 nm–2.16 nm. Dark and under illumination current–voltage (I–V) characteristics of the n-ZnO/
p-Si heterojunction photodetectors showed an improving recti ̄cation ratio and a decreasing satu-
ration current at longer annealing time with an ideality factor of 3 obtained at 60 min annealing
time. Capacitance–voltage (C–V ) characteristics of heterojunctions were investigated in order to
estimate the built-in-voltage and junction type. The photodetectors, fabricated at optimum
annealing time, exhibited good linearity characteristics. Maximum sensitivity was obtained when
ZnO/Si heterojunctions were annealed at 60 min. Two peaks of response, located at 650 nm and
850 nm, were observed with sensitivities of 0.12–0.19 A/W and 0.18–0.39 A/W, respectively.
Detectivity of the photodetectors as function of annealing time was estimated
الاستاذ الدكتور نادر فاضل حبوبي | Prof. Dr.Nadir Fadhil Habubi | 7755