# Presentation: 402139

## A Platform for Spectroscopic Probe of Electric Field Effects in Complex Materials

**A Platform for Spectroscopic Probe of Electric Field Effects in Complex Materials**
**D.N. Basov**
**University of California, San Diego**

**Outline**
**“****grid electrode” devices for **
**   ****optical spectroscopy**
**Polymers**
**Tunable******** in TiO****2**
**Future work**

## A Platform for Spectroscopic Probe of Electric Field Effects in Complex Materials

**Collaborators**
**Zhiqiang Li**
**Kevin Mikolaitis**
***(UCSD)***
**Gunagming Wang**
**Alan J. Heeger**
***(UCSB)***

**A Platform for Spectroscopic Probe of Electric Field Effects in Complex Materials**
**D.N. Basov**
**University of California, San Diego**

## gate

**Semiconductors**
**Transition metal oxides**
**Organic molecular crystals**
**Polymers, nano-tubes, more...**

**gate**

**                            ****oxide                              **

**CRYSTAL**

**FETs: ubiquitous in nature and technology**

**Outstanding alternative to chemical doping!**

## Electrostatic doping: long standing challenges

**FETs:**
**Semiconductors**
**Transition metal oxides**
**Organic molecular crystals**
**Polymers, nano-tubes, more...**

**gate**

**                            ****oxide                              **

**CRYSTAL**

** ****Charge dynamics in **
**  ****accumulation layer?**
**Evolution of the electronic  **
** ****structure?**
**Disorder, localization and **
** ****self-organization?**
**Band-like transport versus **
** ****hopping in polymers/OMC?**
**Role of contacts in the **
** ****observed characteristics?**
** **

** ... ****difficult **

**spectroscopy is highly desirable**

**Tunneling**
**    ****STM**

**IR/**
**optical**

**ARPES**

## detector

**FET structures and IR/optical spectroscopy**

**gate               **

**                    ****oxide ****                             **

**CRYSTAL**

**Sub-THz   THz**

**Far-IR             Mid-IR       Near-IR**

**visible/UV**

**detector**

**IR**
**optical**

## Bottom contact FET geometry  for IR/optical spectroscopy

**S**

**D**

**Crystal (n-Si)**

**oxide**

**Au contacts**

**polymer**

**Bottom contact FET geometry  for IR/optical spectroscopy**

## Bottom contact FET geometry  for IR/optical spectroscopy

**S**

**D**

**S**

**D**

**S**

**D**

**crystal**

**oxide**

**Au contacts**

**polymer**

**Bottom contact FET geometry  for IR/optical spectroscopy**

## Grid-electrode platform for IR probe of electrostatic doping

**(P3HT) **

**S**

**D**

**S**

**D**

**S**

**D**

**crystal**

**oxide**

**Au contacts**

**polymer**

**n-Si**

**TiO****2**

**P3HT/TiO****2****/n-Si**

**Grid-electrode platform for IR probe of**** ****electrostatic doping**

## Grid-electrode platform for IR probe of electrostatic doping

**Poly3-hexylthiophene **
**(P3HT) **

**TiO****2**

**S**

**D**

**S**

**D**

**S**

**D**

**Au contacts**

**Grid-electrode platform for IR probe of**** ****electrostatic doping**

**n-Si**

**P3HT/TiO****2****/n-Si**

**“****Uniform” charge in injection in P3HT**
**  ****on large length scales 20-200 ********m**

**Thin film of a tunable dielectric **

## Grid-electrode platform for IR probe of  tunable dielectrics

**(P3HT) **

**TiO****2**

**S**

**D**

**S**

**D**

**S**

**D**

**Au contacts**

**n-Si**

**Grid-electrode platform for IR probe of****  ****tunable dielectrics**

## Grid-electrode platform and IR probe of  polymer FETs

**(P3HT) **

**SiO****2**

**S**

**D**

**S**

**D**

**S**

**D**

**Au contacts**

**n-Si**

**Grid-electrode platform and IR probe of****  ****polymer FETs**

## a grid-electrode platform for spectroscopic probe of electric field effects in complex materials

**a grid-electrode platform for spectroscopic probe of electric field effects in complex materials**

**Transparent contact geometry for GHz – UV**
**Tunable******** in TiO****2**
**Electrostatic doping P3HT**

**Summary **