EGI-04. บทความที่ประชุมวิชาการ (ระดับนานาชาติ)
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กำลังเรียกดู EGI-04. บทความที่ประชุมวิชาการ (ระดับนานาชาติ) โดย ผู้เขียน "Sanya Khunkhao"
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รายการ Optical profiling on lateral spreading of spacecharge-region metal-semiconductor-metal structures(2555-08-04T16:19:20Z) Sanya KhunkhaoOptical profiling on lateral spreading of space-chargeregion properties of Schottky-barrier metal-semiconductormetal (MSM) structures have been investigated experimentally. Making use of a planar molybdenum/n-type silicon /molybdenum (Mo/n-Si/Mo) MSM structure with a wide electrode separation, one-dimensional (1D) profiling of optical– beam intensity distribution from a helium-neon (He-Ne) laser was carried out. It was also confirmed that, in addition to existing photosensing function, the sensitivity (output photocurrent) of such a structure could be controlled by an applying bias via lateral spreading of the surface space-chargeregion (SCR) at the side of the Schottky-junction reversebiased.รายการ Optical-beam profiling by bias-controlled metal-semiconductor-metal structures(APAC-SILICIDE 2006, 2549-06-22) Sanya KhunkhaoRecently we have shown experimentally that a planar metalsemiconductor- metal(MSM) structure having a wide separation between the two metal electrodes exhibits not only the function of a basic optical sensor but also optical sensitivity field-controllable by the bias applied [I]. In this study, we present the experimental results of onedimensional (ID) optical-beam profiling properties of an MSM structure as its application. To our knowledge, no study has appeared on such an application of planar MSM structures.รายการ Photoinduced on laterally spreading of space-chargeregion(Proceedings of the 2006 Electrical Engineering/ Electronics, Computer,, 2549-05-10) Sanya KhunkhaoPhotoinduced on lateral spreading along the surface of space-charge-region (SCR) of planar metal-semiconductor-metal (MSM) structures have been investigated. This purpose for the SCR of such a structure plays a key role in generating photocurrent and thus, in dc and/ or ac scheme, the wider SCR along the active surface is better from the efficiency point of view. To study the SCR along the surface of MSM structures, we prepared planar MSM structures leaving the undepleted region between the electrodes. We examined their SCR spreading through the photocurrent-bias voltage characteristics.The experimental results were compared with the numerical simulation using a quasi – ID model of such a planar structure. Since the depleted region along the surface would be much more sensitive to the incident illumination than the undepleted region, increase in bias causes the increase in the depletion width and thus detected photocurrent.รายการ Shot noise due to carrier generation in planar metal-semiconductor-metal optical sensors structures(2555-08-04T16:11:42Z) Sanya KhunkhaoLow frequency 3-100 kHz shot noise (white noise) emerging from photoinduced current in Mo/n-Si/Mo structures leaving undepleted region has been observed under different bias and optical intensity conditions. The measurements revealed that the current noise observed depends not only on the illumination intensity levels but also on bias voltage. The current noise observed is expressed as 2()2SqIωΓ= and analyzed, where I and2Γis the average current and noise factor, respectively. The measurements reveal that2Γhas strong bias dependence, lying to about unity corresponding to simple shot noise. Such experimental results are explained, stating that the reduction of crosscorrelation between drift and diffusion currents and autocorrelation of drift current component determining the level of noise occurs with decrease in SCR width bias-dependent. To explain the behavior of observed noise more properly, we propose, in addition to the mechanisms above, that the reduction in autocorrelation effect of each current component plays an important role to decrease the relevant noise to such extremely low levels.รายการ Voltage-controlled of photocurrent in silicon planar metal-semiconductor-metal structures(2555-08-05T15:18:17Z) Sanya KhunkhaoThe bias-controllable photocurrent characteristic by using planar MSM structures with both depleted and undepleted regions under dc and ac optical illumination condition has been proposed at the active area. The structure has two co-planar Mo/n-Si Schottky-barrier junctions on silicon of resistivity 9-12 Ω-cm and the electrode separation is 20 m. By introducing an undepleted region between Schottky barriers on both sides, the depleted region width at the front surface under illumination varies with bias applied, where this region would be more sensitive to optical quantity than the undepleted region to generate the photocurrent. Therefore, this structure is expected to show the output photocurrent as the function of not only optical illumination intensity but applied bias due to laterally spreading of space-charge-region (SCR). Making use of planar molybdenum n-type silicon molybdenum (Mo/n-Si/Mo) structures, it has been experimentally demonstrated that such a structure exhibits voltage-controllability of photocurrents whilst maintaining the inherent function converting optical signal into electronic signal. An appreciable improvement in obtaining output photocurrent was confirmed from both dc and low frequency 100Hz-100 kHz photoresponse properties. It was found that this structure shown an appreciable voltage controllability of the photocurrent of this structure.