Electron-beam fabricated titanium and indium tin oxide position-sensitive detectors

This work reports on the development of an optical position sensitive detec tor (PSD) which exhibits highly linear output characteristics comparable to complex multilayer sensors and which is based on a simple, two-stage fabri cation procedure. Further advantages of this device include the potential f or large-area surfaces and the production of comparatively large output sig nals requiring no amplification or external biasing. Most of these studies were carried out on a Schottky barrier (SB) Structure based on crystalline p-silicon and electron-beam evaporated titanium and operated under focused white light. As a comparison of output behaviour, a second testing run was carried out using a red laser diode. The devices had metal layer thicknesse s ranging from 2000 Angstrom to 180 Angstrom and results showed that the hi ghest sensitivities and lowest nonlinearities occurred with PSDs having thi nner titanium films. The overall best results were obtained using white lig ht in photovoltaic mode, i.e. with no external biasing. Additionally, we co mpared these titanium devices to electron-beam deposited indium tin oxide ( ITO) devices, and found that the ITO series had much lower outputs and high er nonlinearities. These latter devices were considered to be heterojunctio n structures of n-ITO/p-Si.