铟掺杂氧化镓日盲深紫外探测器

The In-Doping Gallium Oxide Solar-Blind Deep Ultraviolet Detector

摘要:

掺杂可以使Ga2O3通过带隙调制显著影响其光吸收特性和电学特性,从而提升光电探测器的性能.因此,本文用PECVD法制备In掺杂β-Ga2O3薄膜,研究了掺In对β-Ga2O3基日盲光电探测器性能的影响机制和应用潜力.该探测器具有优异的深紫外光响应特性,在5 V偏压,光强275 μW/cm2^的254 nm波长光照下光电流达到μA级别,最大光响应度可达480 mA/W,探测度达到6.42×1013 ^Jones,同时还具有235%的外量子效率以及2.15的光电导增益,最大光暗电流比接近106^。高温生长更有利于In的掺入,相对于不掺In情况,相同光照和偏压条件下掺In后β-Ga2O3薄膜光电流明显增大.薄膜中的氧空位与晶格缺陷会对光电探测器性能产生关键影响,其中高占比的表面氧空位通过吸附氧分子和形成表面势垒,影响电子积累与输运,从而在254 nm紫外光照射下提高了光电流响应,而光响应参数随光强增加而减小主要由于载流子的散射与复合.该探测器对深紫外(DUV)低光强的极高灵敏度保证了其在光学传感应用中的巨大潜力,此研究还为高效率In掺杂Ga2O3的深紫外光电探测器提供了新的设计思路.

Abstract:

Doping can notably influence the optical absorption characteristics and electrical properties of Ga2O3 via bandgap modulation, thus improving the performance of photodetectors. This work utilized plasma-enhanced chemical vapor deposition (PECVD) to fabricate indium (In)-doped gallium oxide (Ga?O?) films and investigated the influence mechanism and application potential of In doping on the performance of β-Ga2O3 based solar blind photodetectors. This photodetector demonstrates remarkable deep ultraviolet response properties, reaching a photocurrent level of microamperes under 5 V bias and 275 μW/cm2 illumination at a wavelength of 254 nm. The photodetector achieved a maximum responsivity of 480 mA/W, a detectivity of 6.42×10¹³ Jones, an external quantum efficiency of 235%, and a photoconductive gain of 2.15 and a maximum photo-to-dark current ratio is close to 10?, demonstrating the extremely high sensitivity of In-doped Ga?O? to low DUV light intensities and establishing its significant potential in optical sensing applications. High-temperature growth facilitates the doping of Indium, resulting in a marked increase in the photocurrent of β-Ga2O3 films with Indium doping under identical illumination and bias conditions when compared to those without Indium doping. The presence of oxygen vacancies and lattice defects in the films significantly impacts the performance of the photodetector, with surface oxygen vacancies influencing electron accumulation and migration through the adsorption of oxygen molecules and the formation of surface barriers. Consequently, this enhances the photocurrent response under 254 nm ultraviolet light, whereas the optical response parameters diminish with rising light intensity, mainly due to scattering and recombination of charge carriers. This study provides a comprehensive discussion on the fabrication methods and photoelectronic characteristics of In-doped Ga?O? films. Our findings offer new insights into the design of high-efficiency In-doped Ga?O? deep ultraviolet photodetectors and open new avenues for the application of PECVD technology in semiconductor materials.