Probing the electrical transport properties of intrinsic InN nanowires

Abstract

We have studied the electrical transport properties of intrinsic InN nanowires using an electrical nanoprobing technique in a scanning electron microscope environment. It is found that such intrinsic InN nanowires exhibit an ohmic conduction at low bias and a space charge limited conduction at high bias. It is further derived that such InN nanowires can exhibit a free carrier concentration as low as ∼1013 cm−3 and possess a very large electron mobility in the range of 8000–12 000 cm2/V s, approaching the theoretically predicted maximum electron mobility at room temperature. In addition, charge traps are found to distribute exponentially just below the conduction band edge, with a characteristic energy ∼65 meV.

Extending group‐III nitrides to the infrared: Recent advances in InN

“…In the past several years, significant progress has been made to overcome these challenges. For instance, with improved epitaxial growth process, the background electron concentration can be reduced to low 10 17 and 10 13 cm −3 ranges in planar and nanowire structures, respectively . The measured low 10 13 cm −3 approaches to that of intrinsic InN at room temperature.…”

“…Recently, with an improved MBE growth process and carefully controlled growth conditions, intrinsic InN nanowires were realized, with the electron concentration and mobility in the ranges of 10 13 cm −3 and 12 000 cm 2 /V s at room temperature, respectively . The growth was performed using a Veeco GEN II MBE system on Si substrate.…”

“…InN, with its narrow band gap (∼0.65 eV) , holds the key to extend the operation wavelengths of group‐III nitride optoelectronic devices from the ultraviolet and visible to the near‐infrared spectral range . InN also possesses many extraordinary attributes, including a very small electron effective mass, extremely high electron mobility (12 000 cm 2 /V s), and large saturation velocity (10 8 cm/s), which are ideally suited for applications in ultrahigh‐speed electronic devices . Moreover, the growth/synthesis temperature of InN is relatively low (500 °C, or less), which is compatible with the complementary metal‐oxide‐semiconductor (CMOS) thermal budget.…”

Photoluminescence properties of Mg-doped InN nanowires

“…Indium nitride (InN) has shown tremendous promise for ultrahigh-speed optoelectronic device applications in the infrared (IR) spectral regime due to the narrow bandgap ($0.65 eV) and extremely high electron mobility ($12 000 cm 2 /V s) at room temperature. [1][2][3][4][5] Critical for such device applications is the realization of p-type InN. Although extensive studies have been performed on Mg-doped InN films, 6-12 the achievement of p-type conduction has remained elusive, due to the presence of high background electron concentration and surface electron accumulation.…”

“…27 A separate study on the surface charge properties of these samples indicate that the near-surface Fermi-level is located 0.15-0.25 eV below the conduction band edge, which is similar to that measured from intrinsic InN nanowires, 21 indicating that the background electron concentration is possibly in the range of 10 13 to 10 15 cm À3 based on previous studies. 4 Direct measurements of p-type conduction and free hole concentration of such nanowires were reported elsewhere. 24 The power dependent PL properties of the low-doped sample were first investigated.…”