Large Lateral Photovoltaic Effect in Metal-(Oxide-)Semiconductor Structures

Abstract

The lateral photovoltaic effect (LPE) can be used in position-sensitive detectors to detect very small displacements due to its output of lateral photovoltage changing linearly with light spot position. In this review, we will summarize some of our recent works regarding LPE in metal-semiconductor and metal-oxide-semiconductor structures, and give a theoretical model of LPE in these two structures.

The Effects of MOS Layers on Sensing Properties of MOS Photosensor

“…In order to enhance the barrier height and reduce the dark current, a very thin interfacial layer can be inserted in the junction as part of the semiconductor layer [9,10]. Consequently, high potential barrier can be obtained indicating that the thin interfacial layer had modified the barrier height by influencing the space charge region of the semiconductor layer [4]. However, the responsivity of these devices is low as result of impedance mismatch between the air-metal semiconductor system and a significant portion of the incident optical radiation reflection [11].…”

“…A typical application of Schottky barriers photosensor is in position sensitive detector, where fast response times and high signal to noise ratio (>10 5 ) are essential. However, high photovoltaic efficiency conversion is relatively not very important [4].…”

Transient lateral photovoltaic effect in patterned ferromagnetic metal-oxide-semiconductor films

“…8 On the practical side, the LPE has been widely used to develop high precision position-sensitive detectors (PSD). [9][10][11] Among the main challenges for LPE based devices there is optimizing their spatial sensitivity and reaction time. So far the main root to increase spatial sensitivity of the LPE based PSDs has been achieved by the use of metal-semiconductor junctions, and quite recently metal-oxide-semiconductor junctions (MOS) with different types of metals (Ti, Co, .…”

Transient lateral photovoltaic effect in patterned metal-oxide-semiconductor films

“…A laser beam of a few mW was focused into a 10-50 lm spot and the open circuit LPE was measured between two contacts which extended along opposite edges. 5,9,11 In wide devices, the dynamic response is dominated by the barrier capacitance which results in a unipolar (charge-discharge type) response 12 which diminishes in amplitude when the chopper frequency approaches the kHz range. 13 Moreover, the steady state LPE value diminishes substantially when the Co thickness approaches 20 nm.…”

“…5,6 During the last decades, the main way of optimizing the sensitivity of LPE based PSDs has been achieved by the use of metal-semiconductor junctions, and quite recently metaloxide-semiconductor junctions (MOS) with different types of metals (Ti, Co,…). 7,8 The particular interest shown in Co/SiO 2 /Si structures is related to the possibility of developing broadband PSD for the visible, ultraviolet, or infrared range [9][10][11] by adjusting the Co thickness.…”