Characteristics of MSM photodetector based on a porous In 0.08 Ga 0.92 N thin film were reported. Nanoporous structures of ntype In 0.08 Ga 0.92 N/AlN/Si thin films were synthesized by photoelectrochemical (PEC) etching at a ratio of 1:4 of HF:C 2 H 5 OH solution for 15min. The structural and optical properties of pre and postetched thin films were investigated. Field emission scanning electron microscope and atomic force microscope images showed that the preetched thin film has a sufficiently smooth surface over a large region and the roughness increased for porous film. Blue shift has been observed in photoluminescence emission peak at 300 K for porous sample. The photoluminescence intensity of the porous film indicated that the optical properties have been enhanced. A high work function metals (Pt and Ni) were deposited as a metal contact on the porous films. The rise and recovery times of the devices were investigated at 390nm chopped light. Finally, the sensitivity and quantum efficiency were also studied. Porous InGaN, photoluminescence, SMS photodetector. I. INTRODUCTION REAT attention has been received in recent years for the development of photodetectors based on IIInitride semiconductors. Among IIInitride compounds, the ternary InGaN alloys with their band gaps 0.73.4 eV [1] are very promising for photodetectors. MSM photodetectors are subjected to keen interest among different types of detectors because of ease of fabrication, low dark current, small capacitance, and the suitability for integration in optical receivers [2]. Many research groups [3][5] have extensively fabricated MSM photodetectors based on GaN, but studies on MSM photodetectors based on InGaN are limited. Porous III nitride compounds are promising materials for optoelectronic [6], chemical and biochemical sensors [7] because of their unique optical and electronic properties compared with their bulk counterparts [8], [9], but the reports on it are still very rare [10]. Researchers [11][13] have used photoelectrochemical (PEC) etching to synthesize porous GaN, whereas Abud et al. [14] utilized this technique to produce porous InGaN for the first time. In this work, we report the fabrication and characterization of MSM Saleh H. Abud is with the NanoOptoelectronics Research and Technology (N.O.R) Laboratory, School of Physics, Universiti Sains Malaysia, 11800 Penang, Malaysia. (phone: +60 134743701; fax: +60 46579150; email: salehhasson71@gmail.com). Z. Hassan and F. K. Yam are with the NanoOptoelectronics Research and Technology (N.O.R) Laboratory, School of Physics, Universiti Sains Malaysia, 11800 Penang, Malaysia. (email: zai@usm.my, yamfk@ yahoo.com). photodetector based on porous InGaN. II.EXPERIMENTAL PROCEDURE In this work, we used commercial unintentionally doped n type In 0.08 Ga 0.92 N/AlN grown on two inches diameter Si(111) substrate. The thickness of the InGaN thin film is 1Im. The native oxide of the samples was initially removed using NH 4 OH:H 2 O (1:20), followed by HF:H 2 O (1:50). Boiling aqua regia HCl:HNO 3 (3:1) was subsequently used to clean the samples. Porous InGaN synthesized using the UVPEC etching technique. The etching cell was made from Teflon with a platinum wire as a cathode and an InGaN wafer as an anode. The samples were then etched with 1:4 of HF (49%): C 2 H 5 OH (99.99%) solution under UV lamp illumination and a constant current density (25 mA/cm 2 ) for 15min. All experimental processes were conducted at room temperature. Field emission scanning electron microscope (FESEM, Model FEI Nova NanoSEM 450) and atomic force microscope (AFM, Model Dimension EDGE, BRUKER) were used to determine the surface morphology, whereas the optical properties of the thin films were investigated using photoluminescence spectroscopy system (PL, Model Jobin Yvon HR 800 UV). A high work function metals Pt and Ni contacts of 200nm thickness were deposited on the thin films using radio frequencymagnetron sputtering system and thermal evaporator for Pt and Ni, respectively. III. RESULTS AND DISCUSSION Fig. 1 shows the FESEM image of the nIn 0.08 Ga 0.92 N thin film grown on Si(111) substrate. In Fig. 1 (a) the image reveals that the thin film has sufficiently smooth surface and uniformity over a large region. Inset is the cross section of the film, in which the thickness of the In 0.08 Ga 0.92 N thin film is 1Im with 0.1Im of AlN as a buffer layer. Fig. 1 (b) shows the top view FESEM image of the porous In 0.08 Ga 0.92 N surface, the pores were very regular with sizes around 60100nm. Fig. 1 FESEM image of the (a) preetching, (b) postetching MetalSemiconductorMetal Photodetector Based On Porous In 0.08 Ga 0.92 N Saleh H. Abud, Z. Hassan, F. K. Yam G World Academy of Science, Engineering and Technology International Journal of Nuclear and Quantum Engineering Vol:7, No:12, 2013 1002 International Scholarly and Scientific Research & Innovation 7(12) 2013 ISNI:0000000091950263 Open Science Index, Nuclear and Quantum Engineering Vol:7, No:12, 2013 publications.waset.org/9996801/pdf