Submicron sensors of local electric field with single-electron resolution at room temperature

Abstract

We describe probes of a local electric field, which are capable of detecting an electric charge as small as the charge of one electron e, operational under ambient conditions and having a spatial resolution down to 100nm. The submicron-sized probes were made from a high-density high-mobility two-dimensional electron gas, which is sensitive to the presence of electric charges near its surface. We demonstrate the possibility of using such microprobes for life-science applications by measuring an electric response of individual yeast cells to abrupt changes in their environment.

Multifunctional semiconductor micro-Hall devices for magnetic, electric, and photo-detection

“…Similar results are found for the 1 lm and 4 lm devices. 18 The SGM images are similar to those reported previously 3,23 and can be understood by considering the effect of the local tip-induced potential well/barrier on the current flow near the voltage leads in a similar way to the discussion of the SPVM images. Here, the charged tip alters the electron density Dn beneath the tip via capacitive coupling to the 2DEG.…”

“…Proceeding with the analysis, we deduce a charge responsivity for the 2 lm device of R Q ¼ DV xx / DQ Tip % 240 nV/e at a 10 lA bias current and a charge sensitivity of V th /R Q % 0.05 e/ͱHz. This sensitivity is significantly greater than that of the previous reports of 2DEG Hall cross structures 3 and is comparable to the best reported singleelectron transistor sensitivity at RT. 26 Sensitivities derived for the 1 and 4 lm devices are given in the supplementary material.…”

“…Using the numbering convention shown in Fig. 5(a), the transverse and longitudinal resistances are R xy ¼ A 2,3]. N i is the number of open conduction channels in lead i and T ij is the transmission coefficient between lead i and j calculated using the Gollum quantum transport method 32 as described in Refs.…”

“…While the magnetic sensing attributes of micro-Hall devices based on high mobility 2D electron gas (2DEG) systems are well known, 1,2 the sensitivity of the transverse voltage output to local electric fields (in zero magnetic field) has only recently been investigated and shows the capability for detecting single electron charges. [3][4][5] In this letter, we study the real-space voltage response and sensitivity of InSb 2DEG micro-Hall devices to local electric (E) field, magnetic (B) field and photo-excitation, at room temperature (RT) using electrical and magnetic scanning gate microscopy (SGM) and scanning photovoltage microscopy (SPVM), respectively. SGM and SPVM have been used by numerous groups to study local transport phenomena in buried semiconductor 2DEG nanostructures.…”

Improving gas sensing properties of graphene by introducing dopants and defects: a first-principles study

“…Due to its unique structural, mechanical and electronic properties, graphene becomes an important candidate for numerous potential applications, ranging from composites [2,3], gas sensors [4,5], spintronic devices [6] and transparent electrodes for light emitting diodes and photovoltaics [7][8][9]. Graphene-based electronics should benefit from its exceptional high mobility of charge carriers high stability.…”