التاثيرات الكهربائية والبصرية لتشويب اغشية اوكسيد الخارصين (ZnO) المكونة لمتحسس الاشعة فوق البنفسجية بالفضة == Electrical And Optical Effects Of Ag Doped ZnO Thin Film Based MSM UV Photodetectors
Author name:
محمد وسام ناجي
Supervisor name:
منير عبود هاشم | غصون محسن علي
General topic:
Electrical, Electronic and Communications Engineering
Specific topic:
Electronics and Communications Engineering
Degree:
Master
University:
Mustansiriyah University - College Of Engineering - Department Of Electrical Engineering
Language:
English
University location:
Baghdad
First pages:
34T539 - p.pdf
Abstract:
يستخدم اوكسيد الخارصين (ZnO) لكشف الاشعة فوق البنفسجية وذلك لكبر فجوة الطاقة وكبر طاقة اثارة الربط لهذا الشبه موصل. اوكسيد الخارصين كذلك يمتلك سرعة اشباع عالية وفولتية انهيار عالية. في هذا العمل تم تصنيع متحسس اشعة فوق بنفسجية نوع (معدن - شبه موصل - معدن) با | Zinc Oxide (ZnO) has been commonly used for ultraviolet detection due to large band gap and excition binding energy. ZnO has high breakdown electrical field, also has a much larger saturation velocity. In this work three ultraviolet Metal Semiconductor Metal (MSM) photodetectors were fabricated, based on ZnO and Silver (Ag) doped Zinc Oxide (SZO) with (2% and 4 % doping ratios) thin films. The technique used to prepare the thin films was sol - gel and spin coating technique by using Si (100) p - type. Silver interdigitated (IDT) electrodes were deposited on the films by a vacuum coating deposition technique to form the three devices.The electrical properties for the fabricated photodetectors (PDs) were studied using Semiconductor Characterization System (SCS) at room temperature ( 27 C^o). The applied voltage was in the range of ( - 5 to 5) V.The SEM images showed a non - uniform distribution of the Ag dopants, these dopants formed clusters and these clusters increased as the amount of Ag dopants increased. The mobility, carrier concentration, and roughness for the SZO films increased when compared to undoped film. The optical bandgap and the transmittance are decreased when the doping ratio is increased. The saturation current (I - S) was decreased by a factor of 4, and 12 for the devices based on Ag doped ZnO (with 2% and 4 % doping ratios) thin films, respectively. The sensitivity was significantly increased with increasing the doping ratio. This enhancement attributed to the roughness of the Ag dopants (clusters). The detectivity was increased for the devices based on SZO films. The high detectivity with low saturation current made the devices based on SZO films suitable for optoelectronic applications and integrated circuits. From the experimental data and analysis, it was found that the PD with ZnO : Ag 4 % doping ratio has higher responsivity and gain of 0.523 A/W and 257 , respectively. This is confirmed by thin film and device characterization which makes this PD suitable for UV detection purposes.
