Realization of a Self-Powered InGaZnO MSM UV Photodetector Using Localized Surface Fluorine Plasma Treatment

Abstract

Metal−semiconductor−metal (MSM) photodetectors (PDs) are used for optoelectronic integrated circuits (OEICs) because they allow easy integration with a preexisting circuit. However, traditional MSM PDs require an external bias to separate the electron−hole pairs because they have a symmetrical structure. This study proposes a method to create an asymmetric Schottky barrier height in a MSM PD with a symmetrical interdigital electrode. A localized surface fluorine plasma treatment is applied to a specific area of the a-IGZO film underneath the contacts of the MSM PDs, which produces a localized oxygen deficiency. The photocurrent spontaneously diffuses because there is an asymmetric Schottky barrier. This gives the device self-powering characteristics. The a-IGZO MSM PD with a symmetrical interdigitate electrode operates at a zero bias and has a responsivity of 5 mA/W. The open-circuit voltage under illumination at 365 nm (2 mW/cm 2 ) is 0.20 V. This study demonstrates that this method is applicable to other MSM PDs, particularly those that use an amorphous oxide semiconductor as the active layer.

Easily Processable Cu2O/Si Self-Powered Photodetector Array for Image Sensing Applications

“…The rise/−decay time (τ r /−τ d ) is defined as the time for the current to increase (decrease) from 10 to 90% (90−10%) of its steady maximum values under illumination. 5 The calculated values for τ r and τ d are 10.49 and 9.87 ms, respectively. The Cu 2 O/Si heterojunction PDA has a much faster response than that of other PDAs because it is selfpowered.…”

“…PDA does not exhibit a significant persistent photocurrent effect. The rise/–decay time (τ r /−τ d ) is defined as the time for the current to increase (decrease) from 10 to 90% (90–10%) of its steady maximum values under illumination . The calculated values for τ r and τ d are 10.49 and 9.87 ms, respectively.…”

“…In the last decade, photodetectors (PDs) are highly desired for applications in many fields, such as optical communications, health monitoring, target detection, and remote sensing. − The most important application of PDs is as sensing units for a photodetector array (PDA) in an imaging system. − There are two categories of PDA in the perspective of built-in potential: those with built-in potential (e.g., p–n junctions) and those without built-in potential (e.g., metal–semiconductor–metal; MSM). , The monolithic design of an MSM-type structure is suited for two-dimensional array layouts, but the device structure is symmetrical, so there is no built-in potential . The p–n junction-type PD is widely used for PDAs because it has a self-powered characteristic, a high signal-to-noise ratio, and a fast response. , Most PDAs that use a p–n junction use a top-down method to produce the mesa structure for pixel isolation, , but dangling bonds form on the mesa sidewalls after the wet etching process, so there is a large surface leakage current .…”

Realization of a Self-Powered InGaZnO MSM Ozone Sensor via a Surface State Modulated Photovoltaic Effect

“…Self-powered devices have become a popular research topic because they save energy and have less stringent working space requirements. − For example, a self-powered photodetector can harness ambient light energy to drive the device at zero bias. − This idea has motivated researchers to develop self-powered gas sensors with the assistance of the photovoltaic (PV) effect. , Metal oxide semiconductors (MOSs) are the most common materials for gas sensing due to their high sensitivity, fast response, low cost, and easy processing. , However, MOS-based gas sensors require an external bias to provide two functions: (1) provision of a readout signal that is generated by applying a constant bias current and measurement of the resistance changes and (2) provision of the activation energy required for gas adsorption and desorption on the surface. , The built-in electric field of a p–n heterojunction structure is usually used to create the PV effect for self-powered gas sensors. − Nevertheless, the vertical structure of the p–n heterojunction, which has two different contact metals on opposite sides, does not conform to the monolithic design, so it is difficult to integrate this structure with standard very-large-scale integration (VLSI) circuitry . Metal–semiconductor–metal (MSM) devices have a simple planar structure with an interdigital electrode.…”

Heterogeneous metal oxide channel structure for ultra-high sensitivity phototransistor with modulated operating conditions

“…In flexible display electronics, the wide bandgap and high mobility of amorphous indium gallium zinc oxide (a-IGZO) provides excellent UV sensing performance and compatibility with the industrial manufacturing process of display panels. [9][10][11][12] Furthermore, the low-temperature thin-film deposition process can be applied to flexible plastic substrates. A-IGZO has thus become an emerging candidate for active layer materials in flexible sensor applications.…”