Direct Growth of Graphene Nanowalls on Silicon Using Plasma-Enhanced Atomic Layer Deposition for High-Performance Si-Based Infrared Photodetectors

Abstract

Development of materials and structures for cost-effective and room-temperature-operated infrared photodetectors (PDs) is highly required for security, telecommunications, and environmental sensing fields. Here, we report a method to directly grow large-area graphene nanowalls (GNWs) on the Si substrate by using the plasma-enhanced atomic layer deposition (PEALD) technique and high-performance GNWs-Si heterostructure infrared PDs based on the GNWs. We develop a PEALD protocol by using benzene as the carbon source and formic acid that provides oxygen to assist GNW growth on the Si substrate. Our PEALD-grown GNWs exhibits much better light absorption and in-plane electrical properties as compared to the GNW grown by conventional methods on the Si substrate. Our simple GNW-Si Schottky junction-based self-powered infrared PD exhibits a high responsivity of 15 mA/W at 1342 nm, a fast response speed of 43 μs for rise time and 69 μs for decay time, and a high specific detectivity of 1.5 × 1011 cm Hz1/2/W under a test condition of 10,000 Hz. Our study opens a promising venue to directly grow graphene materials on Si for Si-based optoelectronics.

Chemical Vapor Deposition of Graphene on Self-Limited SiC Interfacial Layers Formed on Silicon Substrates for Heterojunction Devices

“…Moreover, the peaks at ∼2685 and ∼2940 cm –1 belong to 2D and D + G bands of graphene, respectively. These findings confirmed that the PECVD grown GNWs were polycrystalline in nature. , Since the morphology of GNWs primarily comprises three components such as horizontal few-layered graphene called basal layers or buffer layers, vertical free-standing few-layered graphene or carbon nanosheets, and edges of few-layered graphene (as shown in Figure a), the GNWs have a high ratio of edge atoms and contain many sharp and vertically pointed edges (as shown in Figures S9a and a–f). Hence, the strong D peaks originated from a large number of domain boundaries and edges of H-terminated graphene. , These observations were consistent with previous works on PECVD grown GNWs. , For all the samples, the D/G peak ratios of the grown GNWs were high (>1), whereas the 2D/G ratios were low, which indicated that the PECVD grown GNWs were few-layered graphene with high defect density. ,,− …”

“…Figure S9a shows the surface morphology of the PECVD grown graphene on the untreated Si(100) substrate for 2 h. The formation of vertical graphene sheets (VGS) or GNWs with curved morphologies on the whole Si(100) substrate was observed. Obviously, the vertical height of the GNWs can easily be tuned by varying the growth time as demonstrated in our previous study Figure S9b shows the corresponding high-resolution C 1s spectrum of PECVD grown GNWs on pristine Si(100) substrate.…”

“…Obviously, the vertical height of the GNWs can easily be tuned by varying the growth time as demonstrated in our previous study. 53 Figure S9b shows the corresponding highresolution C 1s spectrum of PECVD grown GNWs on pristine Si(100) substrate. The spectrum is fitted with three peaks corresponding to C�C (∼284.8 eV), C−H (∼285.2), and C− O (∼285.8 eV).…”

Recent Progress on Graphene Flexible Photodetectors

“…Over the past few years, various attempts have been made to improve the performance of graphene PDs. Among them, plasma enhancement [ 59 ], resonant cavity enhancement [ 60 ], and heterostructure recombination [ 61 ] are widely explored [ 62 ]. On the other hand, for photodetectors that need to detect specific wavelengths, other wavelengths can be filtered out in different ways.…”

Graphene/Si Heterostructure with an Organic Interfacial Layer for a Self-Powered Photodetector with a High ON/OFF Ratio

“…Photodetectors (PDs) are widely used in various fields of military and daily life especially for imaging, telecommunications, sensing, and so on. Therefore, high performance and low power consumption are of crucial importance for PDs with high detectivity and fast response speed. − A self-powered PD that can work at 0 V bias helps to achieve high detectivity and low power consumption. , In the meantime, graphene materials with unique optical and electronic properties have attracted a lot of attention. , Si and graphene in direct contact can form a reliable Schottky junction, and therefore, photogenerated carriers can be effectively separated at the junction without applied voltage. − Moreover, several graphene/Si heterostructure-based PDs have successfully been demonstrated. − However, the interface trap states coupled with a low Schottky junction barrier reduce response speed and increase noise current, which eventually hinder their high-performance applications. − …”