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High Responsivity and Detectivity Graphene-Silicon Majority Carrier Tunneling Photodiodes with a Thin Native Oxide Layer
ACS Photonics ( IF 6.5 ) Pub Date : 2018-06-08 00:00:00 , DOI: 10.1021/acsphotonics.8b00247
Hong-Ki Park 1 , Jaewu Choi 1
Affiliation  

A photocurrent amplifier operable at low bias voltages with high responsivity and detectivity is highly demanding for various optoelectronic applications. This study shows majority carrier graphene-native oxide-silicon (GOS) photocurrent amplifiers complying with the demands. The photocurrent amplification is primarily attributed to the photoinduced Schottky barrier height (SBH) lowering for majority carriers. The unavoidably formed thin native oxide layer between graphene and silicon during the wet graphene transfer process plays significant roles in lowering of the dark leakage current as well as photoinduced SBH lowering. As a result, the photocurrent to dark current ratio is as high as ∼12.7 at the optical power density of 1.45 mW cm–2. These GOS devices show a high responsivity of 5.5 AW–1 at an optical power (458 nm in wavelength) of 15 μWcm–2, which corresponds to ∼1400% quantum efficiency. Further the response speed is as fast as a few ten-microseconds. Thus, these GOS majority carrier photodiodes show the highest detectivity (2.35 × 1010 cm Hz1/2 W1–) among previously reported graphene-silicon photodiodes. However, the responsivity decreases with the optical power density due to the increasing recombination rate through the interface states proportional to the optical power density.

中文翻译:

具有薄的天然氧化物层的高响应性和高探测性石墨烯-硅多数载流子隧穿光电二极管

在各种光电应用中,对在低偏置电压下具有高响应性和检测性的光电流放大器提出了很高的要求。这项研究表明,大多数载流子石墨烯氧化硅(GOS)光电流放大器均符合要求。光电流放大主要归因于大多数载流子的光诱导肖特基势垒高度(SBH)降低。在湿法石墨烯转移过程中,不可避免地在石墨烯和硅之间形成了一层很薄的天然氧化层,这在降低暗漏电流以及降低光致SBH方面起着重要作用。结果,在1.45 mW cm -2的光功率密度下,光电流与暗电流之比高达〜12.7 。这些GOS设备显示5.5 AW –1的高响应度在15μWcm –2的光功率(波长458 nm)下,相当于约1400%的量子效率。此外,响应速度高达几十微秒。因此,在先前报道的石墨烯-硅光电二极管中,这些GOS多数载流子光电二极管显示出最高的检测率(2.35×10 10 cm Hz 1/2 W 1–)。然而,由于通过与光功率密度成比例的界面状态的复合率增加,响应度随光功率密度而降低。
更新日期:2018-06-08
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