Browsing by Author "Oral, Ahmet"

Construction of a scanning tunneling microscope and first results

Oral, Ahmet (Bilkent University, 1990)

In this thesis, construction of a Scanning Tunneling Microscope in air is explained. A step motor sample approach mechanism and a tripod scanner are used in the construction. Atomic resolution images of graphite samples ...

Investigation of Si1-xGex alloy formation by using STM

Oral, Ahmet (Bilkent University, 1994)

Linear measurements of nanomechanical phenomena using small-amplitude AFM

Hoffmann, P. M.; Patil, S.; Matei, G.; Tanülkü, A.; Grimble, R.; Özer, Ö.; Jeffery, S.; Oral, Ahmet; Pethica, J. (Materials Research Society, 2004)

Dynamic Atomic Force Microscopy (AFM) is typically performed at amplitudes that are quite large compared to the measured interaction range. This complicates the data interpretation as measurements become highly non-linear. ...

Nano and micro Hall-effect sensors for room-temperature scanning hall probe microscopy

Sandhu, A.; Okamoto, A.; Shibasaki, I.; Oral, Ahmet (Elsevier, 2004)

GaAs/AlGaAs two-dimensional electron gas (GaAs-2DEG) Hall probes are impractical for sub-micron room-temperature scanning Hall microscopy (RT-SHPM), due to surface depletion effects that limit the Hall driving current and ...

Nanomechanics using an ultra-small amplitude AFM

Hoffmann, P. M.; Jeffery, S.; Oral, Ahmet; Grimble, R. A.; Özer, H. Özgür; Pethica, J. B. (Cambridge University Press, 2001)

A new type of AFM is presented which allows for direct measurements of nanomechanical properties in ultra-high vacuum and liquid environments. The AFM is also capable to atomic-scale imaging of force gradients. This is ...

Room-temperature scanning Hall probe microscope (RT-SHPM) imaging of garnet films using new high-performance InSb sensors

Oral, Ahmet; Kaval, Murat; Dede, Münir; Masuda, H.; Okamoto, A.; Shibasaki, I.; Sandhu, A. (IEEE, 2002)

The room-temperature scanning Hall probe microscopy (RT-SHPM) imaging of garnet films using high-performance InSb sensors was discussed. The high-performance InSb micro-Hall sensors were fabricated by optical lithography. ...

RT-SHPM imaging of permalloy microstructures and garnet films using new high performance INSB sensors

Oral, Ahmet; Kaval, Murat; Dede, Münir; Sandhu, A. (IEEE, 2002)

The room temperature scanning Hall probe microscopy (RT-SHPM) imaging of permalloy microstructures and garnet films was discussed. The high performance InSb Hall sensors were used for this purpose. It was shown that the ...

Scanning Hall probe microscopy (SHPM) using quartz crystal AFM feedback

Dede, Münir; Ürkmen, Koray; Girişen, Ö.; Atabak, Mehrdad; Oral, Ahmet; Farrer, I.; Ritchie, D. (American Scientific Publishers, 2007)

Scanning Hall Probe Microscopy (SHPM) is a quantitative and non-invasive technique for imaging localized surface magnetic field fluctuations such as ferromagnetic domains with high spatial and magnetic field resolution of ...

Variable temperature Scanning Hall Probe Microscopy (SHPM) using quartz crystal AFM feedback

Dede, Münir; Ürkmen, Koray; Oral, Ahmet; Farrer, I.; Ritchie, D. A. (IEEE, 2006)

Scanning Hall Probe Microscopy (SHPM) is a quantitative and non-invasive technique for imaging localized surface magnetic field fluctuations such as ferromagnetic domains. In this work, we have eliminated the difficulty ...

Variable temperature-scanning Hall probe microscopy with GaN/AlGaN two-dimensional electron gas (2DEG) micro Hall sensors in 4.2-425 K range using novel quartz tuning fork AFM feedback

Akram, Rizwan; Dede, Münir; Oral, Ahmet (IEEE, 2008)

In this paper, we present the fabrication and variable temperature (VT) operation of Hall sensors, based on GaN/AlGaN heterostructure with a two-dimensional electron gas (2DEG) as an active layer, integrated with quartz ...